'
- 'L', L, el (Chicago trains)
- 'Tis the season
-
- -able and -ible
- -aholic, -oholic and -holic
- -emia or -aemia
- -esque
- -gate
- -phobe vs -phile
- -wise
À
- À la mode
É
- Épée, foil or sabre
A
- A bird in the hand is worth two in the bush
- A cappella
- A cat may look at a king
- A chip off the old block
- A cog in the wheel and a cog in the machine
- A day late and a dollar short
- A dime a dozen
- A fate worse than death
- A feather in one's cap
- A fish out of water
- A la (à la)
- A leg up
- A lick and a promise
- A lot vs. alot
- A method in one's madness
- A miss is as good as a mile
- A or an
- A picture is worth a thousand words
- A piece of work
- A priori
- A shot in the arm
- A shot in the dark and a stab in the dark
- A snake in the grass
- A stone's throw
- A taste of one's own medicine and a dose of one's own medicine
- A watched pot never boils
- A whole nother
- A.D., B.C., B.C.E., C.E.
- a.k.a. or aka
- a.m. and p.m.
- Abandon vs. abandonment
- Abbreviations, acronyms, and initialisms
- Abdicate, abnegate, abrogate
- Abecedarius
- Aberrant
- Abetter vs. abettor
- Abhorrent vs aberrant
- Abided vs. abode
- Ability vs. capability vs. capacity
- Abject vs object
- Abjure vs. adjure
- Abolishment vs. abolition
- Aborted vs. abortive
- About-face
- Above board, above-board or aboveboard
- Above one's pay grade
- Abracadabra
- Abridgment and abridgement
- Absolve vs resolve
- Absorption vs. adsorption
- Abstracter vs. abstractor
- Abstruse vs. obtuse
- Accell
- Accent vs accentuate
- Accept vs except
- Acceptance vs. acceptation
- Access
- Accessorize vs accessorise
- Accessory vs accessary
- Accidental vs occidental
- Acclimate, acclimatise, acclimatize
- Acclimation vs acclamation
- Accord vs. accordance
- According to Hoyle and according to Cocker
- Accost
- Accoutrement
- Acephalous
- Achilles' heel
- Acid test vs litmus test
- Acknowledgement vs. acknowledgment
- Acme vs acne
- Acquaintanceship
- Acronym vs anacronym
- Across the board
- Active voice vs. passive voice
- Actualise vs actualize
- Acute vs chronic
- Ad hoc
- Ad hominem (usage)
- Ad infinitum
- Ad nauseam
- Ad vs. add
- Ad-lib and ad lib
- Adam's apple
- Adam's off ox
- Adamance
- Adapt vs adopt
- Adaptable or adaptive
- Adapter vs. adaptor
- Adaption vs. adaptation
- Add insult to injury
- Addenda vs addendums
- Addicting vs. addictive
- Addiction vs. dependence
- Addition vs. edition
- Addlepated, addlebrained and addleheaded
- Adduce vs educe
- Adjective Definition & List of Examples
- Adjudicate
- Administrate
- Admission vs. admittance
- Adolescence vs adolescents
- Adopted vs. adoptive
- Ads, adds or adze
- Adulting
- Advance vs. advanced
- Advent
- Adventurous vs adventuresome
- Adverbs
- Adverse vs. averse
- Advert vs. avert
- Advertise vs advertize
- Advice vs. advise
- Adviser vs. advisor
- Aegis
- Aeon vs. eon
- Aerie vs airy
- Aerobic vs anaerobic
- Aeroplane vs. airplane
- Aesthetic vs. ascetic
- Aether vs. ether
- Aetiology or etiology
- Affect vs. effect
- Affective vs. effective
- Afflict vs. inflict
- Affluent vs. effluent
- Affluenza
- African-American vs. black
- Afterward vs. afterwards
- Afterward vs. afterword
- Ageing vs. aging
- Agent and recipient nouns
- Ages (hyphenation)
- Aggrandize
- Aggravate
- Aggravate vs aggregate
- Aggravate vs mitigate
- Aggression vs. aggressiveness
- Agitprop
- Agnostic vs. atheist
- Agog or agape
- Agree
- Agreement vs agreeance
- Ahead of the curve vs ahead of the curb
- Ahold
- Aid vs. aide
- Ail vs ale
- Ailment vs aliment
- Ain't
- Air quotes
- Air vs heir
- Aisle vs. isle
- Ajar
- Akimbo
- Alas
- Albeit
- Alcoholism vs dipsomania
- Algorithm vs logarithm
- Alight
- Alimentary vs elementary
- All American or all-American
- All but
- All but vs anything but vs everything but
- All get-out
- All in all
- All of a sudden or all of the sudden
- All right vs. alright
- All that
- All that glitters is not gold
- All together vs. altogether
- All-around, all-round
- Allegation vs accusation
- Alleviate vs elevate
- Alligator vs. crocodile
- Alliterate, literate or illiterate
- Alliteration vs assonance
- Allude vs. elude
- Allusion vs. elusion vs. illusion
- Allusive, elusive or illusive
- Alma mater
- Aloud vs allowed
- Alphabetic vs. alphabetical
- Already vs. all ready
- Also-ran
- Altar vs. alter
- Alter ego
- Alternate vs. alternative
- Alternately vs alternatively
- Although vs. though
- Aluminium vs. aluminum
- Alumna, alumnae, alumni, alumnus
- Always a bridesmaid, never a bride
- Always vs all ways
- Amalgam vs. amalgamation
- Amative or amatory
- Amazeballs
- AMBER alert
- Amber vs ember
- Ambiance vs. ambience
- Ambiguous vs ambivalent
- Ambulance chaser
- Ameliorate vs alleviate
- Amend vs. emend
- Amends vs amends
- America
- American
- American Indian vs Native American
- Amiable vs. amicable
- Amok vs. amuck
- Among vs. amongst
- Among vs. between
- Amoral vs. immoral
- Amount vs. number
- Ampersand
- Amphitheater vs amphitheatre
- Ample
- Amuse vs. bemuse
- An albatross around one's neck
- An arm and a leg
- An historic
- Anachronism
- Analog vs. analogue
- Analogue vs. analogy
- Analyse vs. analyze
- Analyses vs analyzes
- Anamorphic
- Anapest
- Anathema
- Ancillary vs auxiliary
- And yet
- Anecdote vs antidote
- Anemic or anaemic
- Anesthesia vs anaesthesia
- Angel vs angle
- Animal adjectives
- Animate vs adamant
- Annal vs annual
- Annex vs. annexe
- Annual, perennial or biennial
- Anodyne vs analgesic
- Anomalous vs anonymous
- Another string in your bow
- Another think coming
- Ant vs aunt
- Ante- vs anti-
- Antediluvian
- Antennae vs. antennas
- Antichrist
- Antifa
- Antimacassar
- Antlers vs horns
- Antonyms
- Anyday vs any day
- Anymore or any more
- Anyone or any one
- Anyplace
- Anytime vs. any time
- Anyway vs. anyways
- Apart vs a part
- Apartment and flat
- Ape vs. monkey
- Apiary vs aviary
- Apocryphal vs canonical
- Apologetics
- Apologise vs. apologize
- Apoplectic vs apocalyptic
- Apostle
- Apostrophe (poetry)
- Apostrophe Rules
- Apotheosis
- Appal vs. appall
- Appeal to authority
- Appellation vs appellative
- Appetizer or hors d'oeuvre
- Appetizer vs appetiser
- Appositives
- Appraise vs. apprise
- Apprehend vs apprehensive
- Apprehensive vs reprehensive
- Approbation vs approval
- Approbation vs opprobrium
- Appropriate vs. expropriate
- April Fool's or April Fools'
- Apropos
- Arbor or arbour
- Arc vs arch
- Arc vs ark
- Arcane and obsolete
- Archaeology vs. archeology
- Arctic, Antarctic
- Ardor or ardour
- Argot vs ergot
- Argumentative vs. argumentive
- Arise or rise
- Armor vs. armour
- Arnold Palmer
- Around the clock, round the clock
- Around vs. round
- Arouse vs. rouse
- Arrant vs. errant
- Arse vs. ass
- Artefact vs. artifact
- Artesian vs artisan
- As cool as a cucumber
- As crook as Rookwood
- As far as
- As per
- As pleased as Punch
- As the crow flies
- As thick as thieves
- As yet, as of yet
- Ascared
- Ascent vs. assent
- Ascent, ascendance, ascendancy, etc.
- Ascribe vs attribute
- Ascribe vs subscribe
- Askew vs eschew
- Aspersion vs dispersion
- Asphalt, cement, concrete, pavement
- Aspiration vs inspiration
- Assail vs. assault
- Assent vs. consent
- Assignation or assignment
- Assume vs. presume
- Assure, ensure, insure
- Astride
- Astrology vs astronomy
- Asylum
- At a loose end
- At cross purposes
- At loggerheads
- At sixes and seven
- At the drop of a hat
- At the end of one’s rope or at the end of one’s tether
- At the end of the day
- At wits' end
- Ate vs eight
- Atlas
- Attache
- Attain vs. obtain
- Attend to vs. tend to
- Au contraire
- Au courant
- Au fait
- Au pair
- Auger vs. augur
- Aught
- August
- Auld lang syne
- Aural vs. oral
- Auspicious vs suspicious
- Authorise vs. authorize
- Authoritative vs. authoritive
- Autobiography vs biography
- Autocorrect
- Autotune or Auto-Tune
- Autumn vs. fall
- Auxiliary verbs
- Avail
- Avant-garde
- Avenge vs. revenge
- Avocation vs. vocation
- Aw or awe
- Await vs wait
- Award vs reward
- Away vs a way
- Awfully
- Awhile vs. a while
- AWOL
- Awry vs wry
- Ax vs. axe
- Axel vs. axle
- Axiom, adage or epigram
- Axis vs axes
- Aye vs eye
B
- Baby blues
- Baby boomer
- Bachelor’s or bachelors degree and master’s or masters degree
- Back in the day
- Back seat vs. backseat
- Back to the drawing board
- Back up vs. backup
- Backseat driver
- Backward vs backwards
- Backwater or backwaters
- Backyard, back yard, back-yard
- Bacteria vs virus
- Bad hair day
- Bad penny
- Bad rap vs. bad wrap
- Bad vs badly
- Bae vs bay
- Bail vs. bale
- Bailiwick
- Bailout, bail out, and bail-out
- Bain-marie vs double boiler
- Bait vs. bate
- Baker's dozen
- Bald-faced vs. boldface
- Balderdash
- Ball vs bawl
- Balmy vs. barmy
- Baloney vs. bologna
- Bamboozle
- Ban vs. bar
- Band (together) vs. bandy (about)
- Band vs banned
- Bane
- Bankster
- Baptise vs. baptize
- Baptism by fire and baptism of fire
- Bar mitzvah and bat mitzvah
- Barbecue vs. barbeque
- Barbed wire
- Bard
- Bard vs barred
- Bare vs. bear
- Bark vs barque
- Barking up the wrong tree
- Barn burner
- Barnstorm
- Baron vs barren
- Base vs bass
- Based vs baste
- Basis (on a daily basis, on a regular basis, etc.)
- Basket case
- Bastion
- Bated breath vs baited breath
- Bath or bathe
- Baton vs batten
- Batten the hatches
- Battle royal
- Bawdy vs body
- Bawl out
- Bazaar vs. bizarre
- Be patient or have patience
- Beach vs beech
- Bear market, bull market, bearish, bullish
- Beat a dead horse and flog a dead horse
- Beat around the bush
- Beat or beaten
- Beat someone to the punch
- Beat swords into plowshares and beat swords into ploughshares
- Beat vs beet
- Beau vs bow
- Beauty is in the eye of the beholder
- Bechdel test and Bechdel-Wallace test
- Beck and call vs beckon call
- Beckon call
- Beeline
- Been there, done that
- Beer vs bier
- Beg off
- Beg the question (usage)
- Began vs begun
- Beggar belief
- Beggars can’t be choosers
- Begging the question (fallacy)
- Begrudge
- Behalf
- Behavior vs. behaviour
- Behest vs bequest
- Behind the eight ball
- Behold and beholden
- Behoove
- Belated
- Belay vs belie
- Belie
- Bell the cat
- Bell vs belle
- Belle vs beau
- Bells and whistles
- Bellwether
- Bellyache
- Below the belt and hit below the belt
- Benchmark
- Benefactor vs patron
- Benefiting vs benefitting
- Bent or bended
- Bereaved vs. bereft
- Berry vs bury
- Berserk
- Berth vs birth
- Beside oneself and beside the point
- Beside or besides
- Besotted
- Bespeak vs bespoke
- Bespeckled or bespectacled
- Best-laid plans
- Better late than never
- Better vs bettor
- Between a rock and a hard place
- Betwixt
- Beyond the pale
- Bezel vs embezzle
- Biannual vs. biennial
- Biannual, biennial and semiannual
- Biceps and triceps
- Bid, bade, bidden
- Big cheese
- Big fish in a small pond
- Big kahuna
- Big-ups
- Bight vs. bite
- Bill of goods
- Billed vs build
- Bimonthly and semimonthly
- Binded vs. bound
- Binge-watch
- Bingeing or binging
- Bingo
- Birds of a feather flock together
- Bisect vs dissect
- Bisexual or pansexual
- Bit vs. bitten
- Bite off more than one can chew
- Bite one's tongue
- Bite the bullet
- Bite, byte or bight
- Bite-size or bite-sized
- Bivouac
- Biweekly vs semiweekly
- Black Friday
- Black market
- Black out vs blackout
- Black sheep
- Blackball
- Blackmail vs extortion
- Blandish vs brandish
- Blaspheme
- Blatant vs. flagrant
- Blather vs blabber
- Blather vs. blither
- Blench vs blanch
- Blessed vs. blest
- Blew, blown, or blowed
- Blind side vs blindside
- Bling
- Blitzkrieg
- Bloc vs. block
- Blockbuster
- Blond vs. blonde
- Blood brother
- Blood is thicker than water
- Blooper
- Bloviate
- Blow off steam and let off steam
- Blow someone's cover
- Blow your own trumpet and toot your own horn
- Blowhard and windbag
- Blowout vs. blow out
- Blowup vs. blow up
- Blue blood
- Blue collar, white collar
- Bluetooth
- Board vs bored
- Bob's your uncle
- Bobble vs bauble
- Bobbsey twins
- Bodega
- Body politic
- Bogeyman
- Boggle the mind and mind-boggling
- Bohemian
- Bokeh
- Bold as brass
- Bolder vs boulder
- Boldface text
- Bollocks vs bollocking
- Bombogenesis
- Bona fide, bona fides
- Bone of contention
- Bone to pick
- Bone vs debone
- Bonhomie
- Booby hatch
- Boondocks vs boonies
- Boondoggle
- Boot camp
- Boots on the ground
- Booze vs boos
- Border vs boarder
- Bore, boor, boar
- Born with a silver spoon in one's mouth
- Borne vs. born
- Borough, burro, burrow
- Botanic vs. botanical
- Bottom line
- Bough or bow
- Bought the farm and gone for a Burton
- Boughten
- Bound vs. bounded
- Bounteous vs bountiful
- Bourgeois, bourgeoisie
- Bowdlerize
- Bowl vs boll
- Bowled vs bold
- Braggadocio
- Braggart vs bragger
- Braid vs abrade
- Braid vs brayed
- Brain trust vs think tank
- Brainchild
- Brainwash
- Brake vs break
- Brand spanking new
- Brandish vs brand
- Bravado
- Breach, breech, broach
- Bread and butter
- Breadcrumbs, breadcrumb trail and trail of breadcrumbs
- Break a leg
- Break the ice
- Break up vs. breakup
- Breastfeeding, breastfed, breastfeed, etc.
- Breath vs. breadth (vs. width)
- Breath vs. breathe
- Breeches vs britches
- Brews vs bruise
- Brexit and Grexit
- Bric-a-brac and knick-knack
- Brickbat
- Bridezilla
- Bridle vs. bridal
- Brief vs debrief
- Bright vs. brite
- Bring home the bacon
- Bring vs take
- Briton
- Briton vs Britain
- Broach vs. brooch
- Bromide
- Bronx cheer and blow a raspberry
- Brouhaha
- Brownie points
- Browse vs brows
- Brung, brang
- Brussels sprout
- Buck naked, butt naked
- Bucket list
- Buckle up vs buck up
- Buffer vs. buffet
- Bugbear or bugaboo
- Build up vs. buildup
- Building castles in the air
- Bulk, balk, baulk
- Bullion vs boullion
- Bullseye or bull's eye
- Bully pulpit
- Bum-rush vs bum's rush
- Bumpkin
- Bun in the oven
- Bunk vs debunk
- Bunk, bunkum, buncombe
- Bunny vs Bunnie
- Bunt vs Bundt
- Bupkis
- Burgle vs. burglarize
- Burn one's bridges and burn one's boats
- Burn the candle at both ends
- Burned vs. burnt
- Burning the midnight oil
- Burnish vs tarnish
- Burnout vs. burn out
- Bursted
- Burthen
- Bury the hatchet
- Bus stop vs. busstop
- Buses vs. busses
- Busman's holiday
- Bust one's chops and lick one's chops
- Busybody
- But vs. yet
- Butter wouldn't melt in his mouth
- Butterfingers
- Butterfly effect
- Buy, by or bye
- Buzzword
- By and by vs. by the by
- By dint of
- By hook or by crook
- By the skin of one's teeth
- By the way and BTW
- By, bye and buy
- Byproduct
- Bête noire
C
- C'est la vie
- Cabin fever
- Cacao vs. cocoa
- Cache vs cash
- Cache vs. cachet
- Cacti vs. cactuses
- Caddie vs. caddy
- Caduceus vs staff of Asclepius
- Caesarean section, Caesarian, cesarean, etc.
- Cahoots
- Cakewalk
- Caliber vs. calibre
- Call a spade a spade
- Call on the carpet
- Call someone’s bluff
- Call the shots
- Callous vs. callus
- Calumny
- Calvary vs. cavalry
- Calves vs. calfs
- Camaraderie vs comradery
- Can goods or canned goods
- Can of worms vs pandora's box
- Can vs may
- Can't hold a candle to
- Can't vs cant
- Canard
- Canary in the coalmine
- Canceled vs. cancelled
- Candor or candour
- Candy corn
- Cannon fodder
- Cannonball Express
- Cannot or can not
- Cannot see the forest for the trees
- Canny vs uncanny
- Canon vs. cannon
- Cantankerous
- Cantor vs canter
- Canvas vs. canvass
- Capiche, capeesh, capische, etc
- Capital vs. capitol
- Capitulate vs recapitulate
- Capstone, keystone or cornerstone
- Captivate vs capture
- Car hood and car bonnet
- Car park vs parking lot
- Caramel vs carmel
- Carbon copy
- Carbon footprint
- Carburetor vs carburettor
- Card shark vs. card sharp
- Careen vs. career
- Caretaker vs caregiver
- Carnation vs incarnation
- Carnivore, herbivore or omnivore
- Carpe diem
- Carrel vs carol
- Carrot, carat, karat, caret
- Carrot-and-stick
- Carry a torch for someone, torch song and torch singer
- Carte blanche
- Cartography
- Carved in stone, set in stone and written in stone
- Case in point
- Cash cow
- Cash on the nail and cash on the barrelhead
- Cashmere vs Kashmir
- Casket vs coffin
- Cassandra
- Cast aspersions
- Cast pearls before swine
- Caste vs cast
- Casted
- Castigate vs castrate
- Cat got your tongue?
- Catachresis
- Catalog vs. catalogue
- Catalyse or catalyze
- Catcall
- Catch lightning in a bottle
- Catch-22
- Categorize vs categorise
- Catty-corner, kitty-corner
- Caucus
- Caught red-handed
- Cause celebre
- Cauterize vs cauterise
- Cavalcade
- Cavalier
- Caveat
- Caveat emptor
- Cay, quay and key
- Cease and desist
- Cease and surcease
- Cede and seed
- Cede vs. concede
- Ceiling vs sealing
- Cel, cell or sell
- Celebrant or celebrator
- Celiac or coeliac
- Celiac vs celeraic
- Cellar vs seller
- Censer vs censor vs censure vs sensor
- Cent, scent and sent
- Center around or center on
- Center vs. centre
- Centrifugal vs. centripetal
- Centrifuge vs. subterfuge
- Centuries
- Cereal vs serial
- Ceremonial vs ceremonious
- Certainty vs. certitude
- Certifiable
- Cession vs. session
- Chafe vs. chaff
- Chain letter
- Chaise lounge and chaise longue
- Chalk up vs. chock
- Champing at the bit vs. chomping at the bit
- Charade and charades
- Charism vs charisma
- Charlatan
- Charley horse
- Charnel house
- Chasten vs. chastise
- Chatbot
- Chateaus vs chateaux
- Chatty Cathy
- Chav
- Cheap vs cheep
- Check in vs. check-in (vs. checkin)
- Check kiting
- Check up vs. checkup
- Check vs. cheque
- Checkered past and chequered past
- Checkout vs. check out
- Cheek by jowl
- Cheek to cheek vs cheek-to-cheek
- Cherry-pick
- Chews vs choose
- Chic vs. sheik
- Chicanery
- Chick flick and chick lit
- Childcare, child care, child-care
- Childish vs. childlike
- Chili vs. chilly
- Chills down the spine
- Chimera
- Chink vs. kink
- Chinwag
- Chip on your shoulder
- Chips vs. fries
- Choate or inchoate
- Chock-a-block vs chockablock
- Chock-full
- Chopper vs. copter
- Chorale, choral or corral
- Chortle
- Chose vs choose
- Chow vs ciao
- Christmas Adam
- Chump change
- Chunder or chunter
- Chute vs. shoot
- Cinch the deal or clinch the deal
- Cisgender vs transgender
- Cistern vs sister
- Citizen journalism
- Civic vs. civil
- Civil rights and human rights
- Civilise vs. civilize
- Clamor vs clamber
- Claptrap
- Classic vs. classical
- Clause vs claws
- Clauses
- Clean someone's clock
- Clean vs. cleanse
- Cleanup vs. clean up
- Cleave
- Clench vs. clinch
- Clew vs clue
- Click vs clique
- Clickbait
- Client vs. customer
- Cliffhanger
- Cliffs Notes
- Climactic vs. climatic
- Clime vs climb
- Cloak-and-dagger
- Clone
- Close but no cigar
- Close proximity
- Close rhyme
- Close-knit and tight-knit
- Close-minded vs. closed-minded
- Cloth vs clothes
- Cloture vs closure
- Cloying and mawkish
- Co-op vs. co-opt
- Co-ordinate vs coordinate
- Coal, cole or kohl
- Coarse vs. course
- Coast is clear
- Cock and bull story
- Cockamamie
- Coddle and mollycoddle
- Coffice
- Cognate and false cognate
- Coiffure vs coiffeur
- Coin a phrase
- Cold shoulder
- Cold turkey
- Cold-call
- Coliseum vs. colosseum
- Collaborate vs corroborate
- Collectible vs collectable
- Collective nouns
- College vs. university
- Collegial vs. collegiate
- Collision vs collusion
- Collocate
- Collocate vs colocate
- Colon
- Colonize vs colonise
- Color vs. colour
- Coma vs comma
- Comb-over
- Come over vs overcome
- Come-hither look
- Come-to-Jesus moment and come-to-Jesus meeting
- Comedienne
- Comestible vs combustible
- Comeuppance
- Comic vs. comical
- Coming of age
- Comity vs comedy
- Commas
- Comme ci, comme ça
- Commencement
- Commend vs command
- Commentator vs. commenter
- Commiserate vs commensurate
- Common French expressions
- Compared to or compared with
- Compel vs. impel
- Competence and competency
- Complacent vs complicit
- Complacent vs. complaisant
- Complement vs. compliment
- Compose vs. comprise
- Comprise vs compromise
- Compunction vs compulsion
- Computerize or computerise
- Concave vs. convex
- Conceded or conceited
- Conceive vs. perceive
- Concerning
- Concerted
- Conches vs. conchs
- Concurrent vs consecutive
- Condemn vs. condone
- Confidant vs. confidante
- Conflate vs conflagrate
- Conflict of interest
- Congruent vs. congruous
- Conjunctions
- Conjunctions to start sentences
- Connect the dots and join the dots
- Connexion
- Connive vs contrive
- Connote vs. denote
- Conscience, conscious and self-conscious
- Consequential vs consensual
- Conservatory, solarium or sunroom
- Consolation vs constellation
- Conspiracy or collusion
- Constant vs consistent
- Consultative
- Contaminate vs contaminant
- Contemporaneous vs. contemporary
- Contemptible vs. contemptuous
- Content or contented
- Contiguous vs continuous
- Continental breakfast
- Contingency vs contingent
- Continual vs. continuous
- Contract a disease or contact a disease
- Contractions
- Contraption
- Contravene vs contradict
- Contronym and auto-antonym
- Contumely
- Conundrum
- Conversate
- Convivial vs congenial
- Convocation, commencement or invocation
- Cooking the books
- Coon's age
- Coop, coup or coupe
- Cooperate vs. co-operate
- Coordinate adjectives
- Cooties
- Copacetic or copasetic
- Copse vs cops
- Copyright vs. copywrite
- Coral vs. corral
- Cord vs. chord
- Core, corps and corpse
- Corn flour vs cornmeal
- Cornball and corny
- Cornet vs. coronet
- Corollary vs. correlation
- Correspondence vs correspondents
- Corroborate vs cooperate
- Cosmetology vs. cosmology
- Cosplay
- Cosset vs corset
- Costed
- Cosy vs. cozy
- Cottage industry
- Cotton candy or cotton floss or fairy floss
- Couch-surf
- Could care less
- Could have, could've or could of
- Council vs. counsel
- Counsel vs consul
- Counselor vs. counsellor
- Country mile
- Coup de grace
- Cover all the bases
- Covert vs overt
- Covet vs covert
- Cozy English Grammar
- Crack down vs. crackdown
- Crackerjack
- Crap
- Crapshoot
- Crave vs craven
- Crayfish, crawfish, crawdad, etc.
- Crayon vs Crayola
- Cream of the crop
- Creature comfort
- Credible vs. credulous
- Credible, creditable or credulous
- Creek vs creak
- Creeped vs. crept
- Crevasse vs. crevice
- Crick (variant of creek)
- Crier vs. cryer
- Crisis of conscience vs crisis of confidence
- Criteria, criterion
- Criticize or criticise
- Crocodile tears
- Cronyism
- Cross the line
- Cross the Rubicon
- Crowdsourcing vs crowdfunding
- Croze vs crows
- Cruciferous
- Crueler or crueller, cruelest or cruellest
- Crumby vs. crummy
- Cry all the way to the bank
- Cryptid
- Crèche and manger
- Cue vs. queue
- Cul-de-sac
- Culpable vs liable
- Cultural appropriation
- Cum
- Curate's egg
- Curb vs. kerb
- Curds and whey
- Curmudgeon
- Currant vs current
- Currently
- Curricula vs curriculums
- Curriculum vitae vs résumé
- Curry favor
- Cursive vs coercive
- Cursor vs curser
- Cursory vs curse
- Custom vs costume
- Customise vs. customize
- Cut and dried
- Cut off your nose to spite your face
- Cut the mustard
- Cut to the chase
- Cut to the quick
- Cut-throat
- Cutesy
- Cyber-
- Cyberspace
- Cybersquatting
- Cyclist vs. biker
- Cynical
D
- D'oh
- Dactyl
- Dahlesque
- Daily grind
- Dais
- Dam vs. damn
- Damp squib
- Dampen, damper, dampener
- Danglers
- Dangling modifier
- Daresay
- Dark horse
- Data
- Dates and commas
- Davy Jones's locker
- Day in age (day and age)
- Daylight Saving Time or British Summer Time
- De facto
- De rigueur
- Dead as a doornail
- Dead end
- Dead ringer
- Dead set, dead-set, deadset
- Deaf vs deft
- Dealt vs. dealed
- Dear John letter
- Dearth
- Debark or disembark
- Debauchery
- Decathlon, heptathlon, pentathlon, triathlon and biathlon
- Decent vs. descent
- Deceptively
- Decidedly
- Decimate
- Decisive vs divisive
- Deck the halls
- Declarative, imperative, exclamatory and interrogative sentences
- Deconstruction
- Decrepit vs deprecate
- Decry vs. descry
- Decussate vs desiccate
- Deduce vs. induce
- Deduct vs deduce
- Deep-seeded vs. deep-seated
- Deepnet, darknet and deep web
- Deer vs deers
- Defence vs. defense
- Defenestration
- Definite articles
- Definite vs definitive
- Defuse vs. diffuse
- Deign
- Delegate vs relegate
- Deleterious vs detrimental
- Delude vs dilute
- Delusions of grandeur
- Demagogue vs demigod
- Demeanor or demeanour
- Democracy vs republic
- Demon vs daemon
- Demur vs. demure
- Denounce vs. renounce
- Dent vs dint
- Dents vs dense
- Dependant vs. dependent
- Deplane or disembark
- Depose vs dispose
- Deposition vs disposition
- Depository vs. repository
- Depravation vs deprivation
- Deprecate vs. depreciate
- Depute vs dispute
- Derision vs decision
- Derring-do
- Descendant vs. descendent
- Desert vs dessert
- Desolate vs destitute
- Desperate vs disparate
- Despite vs. in spite of
- Destroy vs. destruct
- Deteriorate vs decline
- Detract vs. distract
- Deus ex machina
- Device vs. devise
- Devil is in the details vs. God is in the detail
- Devil take the hindmost
- Devil vs bedevil
- Devil's advocate
- Devil's food cake
- Deviled vs devilled
- Dew, do and due
- Dewclaw
- Dharma and karma
- Diagram
- Dialectal vs. dialectical
- Dialogue vs dialog
- Diametrically opposed
- Diamond in the rough
- Diaspora
- Dibs and calling dibs
- Dice vs. die
- Dichotomy vs discrepancy
- Dichotomy vs paradox
- Dickensian
- Didactic vs pedantic
- Dieresis and diaeresis
- Dietician or dietitian
- Difference vs deference
- Different from, different than, different to
- Diffidence vs difference
- Dike vs. dyke
- Diktat
- Dilapidated
- Dilemma
- Dingo's breakfast
- Dire straits
- Dire vs dyer
- Directional words
- Dirigible or blimp
- Dis vs. diss
- Disabuse, misuse and abuse
- Disassemble vs. dissemble
- Disburse vs. disperse
- Disc vs. disk
- Discombobulate
- Discomfit vs. discomfort
- Disconnect
- Discord vs accord
- Discrete vs. discreet
- Disdain or distain
- Disenfranchise vs. disfranchise
- Disillusion vs. dissolution
- Disinterested vs. uninterested
- Disparity vs disparateness
- Dispatch vs. despatch
- Dispense with vs. dispose of
- Disposed vs. predisposed
- Dissatisfied or unsatisfied
- Dissent vs descent
- Dissociate vs. disassociate
- Distaff
- Distinct vs. distinctive
- Distrust vs. mistrust
- Ditto and ditto mark
- Divers vs. diverse
- Divorcée, divorcé, divorcee
- Do apologize
- Do right by
- Do the math
- Docent
- Dock vs doc
- Dog and pony show
- Dog breed names
- Dog days
- Dog-eat-dog
- Dogged vs dogged
- Doggerel
- Doh, doe or dough
- Dole out vs. doll out
- Dollars to doughnuts
- Dominant vs predominant
- Domino effect
- Don vs dawn
- Don't change horses in midstream
- Don't look a gift horse in the mouth
- Don't's or don'ts
- Done vs dun
- Donner or Donder
- Donnybrook
- Doodle
- Doomsday vs Domesday
- Doppelgänger
- Dos or do's
- Dossier
- Dotage vs senility
- Dotard
- Double dog dare
- Double down vs buckle down
- Double entendre
- Double jeopardy
- Double vs. redouble
- Double whammy vs whammy
- Double-check
- Double-edged sword
- Doublethink, doublespeak or double-talk
- Doubting Thomas
- Doubtlessly
- Doughnut vs. donut
- Douse vs. dowse
- Dove vs. dived
- Down at the heels
- Down in the mouth
- Down the pike vs. down the pipe
- Down the rabbit hole
- Down to the wire
- Downfall vs. downside
- Downplay or play down
- Downright vs outright
- Doxing and doxxing
- Doyen or doyenne vs docent
- Draconian
- Draft vs. draught
- Dragged vs. drug
- Draughts and checkers
- Draw a line in the sand
- Dreamed vs. dreamt
- Dredge vs drudge
- Dregs vs dredge
- Dreidel or dreidl
- Dribble vs. drivel
- Dribs and drabs
- Drier vs. dryer
- Drink drank drunk
- Drink the Kool-Aid
- Drive-by
- Droll
- Drop like flies
- Drop off vs. drop-off (vs. dropoff)
- Drop the ball
- Drop-dead vs drop dead!
- Drum someone out
- Druthers
- Dry goods
- Dry run
- Du jour
- Dual vs. duel
- Duck tape or duct tape
- Dudgeon vs dungeon
- Due diligence
- Due process
- Due to vs because of
- Duly noted
- Duly vs dully
- Dumb down
- Dumb waiter and dumbwaiter
- Dumpster fire
- Dumpster vs dumpster
- Duplicate vs duplicity
- Duplicate vs replicate
- During the course of
- Dwarfs vs. dwarves
- Dwelled vs. dwelt
- Dyed in the wool
- Dyeing vs. dying
- Dystopia or utopia
- Déjà vu
E
- E pluribus unum
- E-book, ebook, eBook
- E-mail vs. email
- E. coli
- E.g. vs. i.e.
- Each other vs. one another
- Ear candy and eye candy
- Earmark
- Earn vs urn
- Earnest vs Ernest
- Earth (capitalization)
- Earthy vs. earthly
- Earworm
- Easter egg
- Eat crow
- Eat humble pie
- Eaves vs eves
- Ecclesiastical and ecclesiastic
- Economic vs. economical
- Economics vs. finance
- Ecumenical
- Eek vs. eke
- Eeny, meeny, miny, mo
- Effable vs affable
- Effete
- Egg someone on
- Eggnog
- Egregious vs gregarious
- Eighty-six
- Either vs ether
- Either vs neither
- Elbow grease
- Elder, eldest
- Electric, electrical, electronic
- Elegy vs. eulogy
- Elephant in the room
- Eleventh hour
- Elfs vs. elves
- Elicit vs. illicit
- Ellipsis
- Elocution vs. locution
- Elvis has left the building
- Em dash (Em rule)
- Embed vs imbed
- Embolization and embolisation
- Emeritus
- Emigrate vs. immigrate
- Eminent vs. immanent vs. imminent
- Emission vs omission
- Emoji vs emoticon
- Emolument vs emollient
- Empathetic vs. empathic
- Empathy vs. sympathy
- Emphasise vs emphasize
- Empire vs umpire
- En dash (En rule)
- En masse
- En route
- En vogue, in vogue
- Enamor vs. enamour
- Enclose vs. inclose
- Endear
- Endeavor vs. endeavour
- Endemic vs. epidemic
- Endorphin
- Energize vs energise
- Enervate
- Enervate vs energize
- Enervate vs. innervate
- Enfant terrible
- England, Great Britain, United Kingdom
- English as a Second Language
- English Classes Online Are The Future
- English Grammar
- English Grammar Revolution
- English in flux: 10 word peeves that should be laid to rest
- English moods (imperative, indicative, and subjunctive)
- English4u
- Engrain vs. ingrain
- Enjoin vs join
- Enmity vs animosity
- Enormity vs. enormousness
- Enquire vs. inquire
- Enrol vs. enroll
- Ensconce vs sconce
- Enthuse
- Entitled vs. titled
- Entomology vs. etymology
- Entree vs entrée
- Envelop vs. envelope
- Envision vs. envisage
- Envision vs. invision
- Envoi vs. envoy
- Epic vs epoch
- Epicenter
- Epidemic vs pandemic
- Epigram vs. epigraph
- Epiphany or Twelfth Night
- Epitaph vs epithet
- Epithet vs sobriquet
- Epitome vs epiphany
- Eponymous
- Equable, equatable, equitable
- Equator vs prime meridian
- Equinox vs solstice
- Equivalence vs. equivalency
- Equivocate vs prevaricate
- Ere vs. err
- Ergo
- Ergonomics
- Erin go bragh
- Erratum, addendum and corrigendum
- Ersatz
- Erupt vs irrupt
- Eschew
- ESL Blues
- ESL Fast
- ESL Resource Center
- esl-lounge
- Esoteric vs archaic
- Especial
- Especially vs specially
- Espouse vs expound
- Espresso vs. expresso
- Esprit de corps
- Estimate vs. estimation
- Estimation or approximation
- Et al.
- Et cetera (etc.)
- Ethereal vs ephemeral
- Ethics vs. morals
- Ethnic vs ethic
- Ethnicity vs. race
- Evacuate
- Evade vs invade
- Even keel
- Even-Steven and Even-Stevens
- Everyday vs. every day
- Everyone vs every one
- Everything happens for a reason
- Evidence vs evince
- Evoke vs. invoke
- Ewe, yew or you
- Ex post facto
- Exacerbate vs exasperate
- Exact revenge vs extract revenge
- Exalt vs. exult
- Exceed vs accede
- Excelsior and wood wool
- Excited vs exited
- Exclamation point
- Excoriate vs execrate
- Excrete vs secrete
- Exculpate vs exonerate
- Exemplary
- Exercise vs. exorcise
- Exhibit vs. exhibition
- Exhort vs extort
- Existent vs. extant
- Existential
- Expatriate vs immigrant
- Expectant vs. expecting
- Expedient vs expeditious
- Expedite vs expedient
- Expiration date and expiry date
- Explicate vs expletive
- Explicit vs implicit
- Exploitative vs. exploitive
- Expose vs exposé
- Expound vs expand
- Extant vs extent
- Extemporaneous
- Extol vs extoll
- Extradite vs expedite
- Extraordinaire
- Extricate vs extirpate
- Exuberant vs exorbitant
- Eyelet vs islet
F
- Fabulist
- Face the music
- Facepalm
- Factious vs facetious
- Factious vs fractious
- Factoid
- Factotum
- Faeces vs feces
- Fail vs flunk
- Fain vs. feign
- Faint of heart
- Faint vs feint
- Fair and square
- Fair dinkum
- Fair to middling vs fair to midland
- Fair vs. fare
- Fairy vs ferry
- Fairy-tale ending
- Fait accompli
- Faker vs fakir
- Fall guy
- Fall on one's sword
- Fallow vs follow
- False flag
- Falsehood, falsity, falseness
- Fame vs defame
- Famous last words
- Famous, infamous and notorious
- Fantods
- Far East, Middle East, Near East
- Far-fetched
- Faraway vs far away
- Faro, farrow or pharaoh
- Farther vs. further
- Fastly
- Fatal vs fateful
- Fatuous vs facetious
- Faun vs. fawn
- Faux
- Faux pas
- Faux-naïf
- Favor vs. favour
- Favorite vs. favourite
- Fay, fey
- Faze vs. phase
- Fearful vs. fearsome
- Feckless
- Feckless vs reckless
- Feeding frenzy
- Feet vs feat
- Fell off the back of a truck
- Feminity vs. femininity
- Ferment or foment
- Ferret out
- Fervent vs. fervid
- Festivus
- Fete
- Few vs phew
- Fewer vs. less
- Fiancé vs. fiancée
- Fiat
- Fiber vs. fibre
- Fiction vs. nonfiction
- Fictional vs. fictitious
- Fiddle while Rome burns
- Fie
- Fiefdom
- Fifteen minutes of fame
- Fifth column
- Fifth wheel vs third wheel
- Fight fire with fire
- Fight tooth and nail
- Figment of one’s imagination
- Figurehead
- File, phial or faille
- Filet vs. fillet
- Filibuster
- Finagle
- Financer vs. financier
- Find vs fined
- Finders keepers
- Finger-licking good
- Fingers crossed
- Finite verb
- Fire and brimstone
- Fire in the hole vs fire in the hold
- Firebrand
- Firefight
- Firefly and lightning bug
- Fireplace vs hearth
- Firing line vs. line of fire
- First aid
- First come, first served
- First floor
- First things first
- First World problem
- First, second and third person
- First-world, third-world
- Firsthand and secondhand vs first-hand and second-hand
- Firstly, secondly, thirdly, etc.
- Fiscal vs physical
- Fish vs. fishes
- Fissure vs fisher
- Fit to be tied
- Fit vs. fitted
- Five o’clock shadow
- Flack vs. flak
- Flagellants vs flatulence
- Flagship
- Flair vs. flare
- Flammable vs. inflammable
- Flash in the pan
- Flash mob
- Flat out
- Flaunt vs. flout
- Flautist vs. flutist
- Flavor of the month
- Flavor vs. flavour
- Flea vs flee
- Flecks vs flex
- Flesh out vs. flush out
- Fleshly vs. fleshy
- Fleur-de-lis
- Flied
- Flier vs. flyer
- Flip one's lid vs. flip one's wig
- Flocks vs phlox
- Floe vs flow
- Flora and fauna
- Flotsam and jetsam
- FLOTUS
- Flounder vs. founder
- Flower vs flour
- Flu vs. flue
- Flue vs flew
- Flummox
- Fluorescent vs incandescent
- Fly in the face of
- Fly in the ointment
- Fly off the handle
- Fly-by-night
- Fob off
- Fodder vs father
- Foe vs faux
- Foist
- Folderol
- Foley
- Follow up, follow-up, followup
- FOMO
- Font vs fount
- Food coma
- Food for thought
- Fool's errand
- Fool's paradise
- Foolproof vs. full-proof
- Foot
- Foot long
- Football fields
- For all intensive purposes (for all intents and purposes)
- For God's sake
- For heaven's sake
- For the birds
- For the purpose of
- For, four and fore
- Fora vs. forums
- Forbear vs. forebear
- Forbidden fruit
- Forbidding vs. foreboding
- Force majeure
- Forceful vs forcible
- Forecast vs. forecasted
- Forego vs. forgo
- Foreword vs. forward
- Formally vs formerly
- Former, latter
- Formulas vs formulae
- Forte
- Forth vs fourth
- Fortnight
- Fortuitous vs. fortunate
- Forty vs. fourty
- Forty winks
- Fosbury flop
- Foul vs. fowl
- Fount of knowledge or wisdom vs font of knowledge or wisdom
- Four-flusher
- Fox guarding the hen house
- Fracking
- Fractious vs fracas
- Fractious vs fraction
- Franken-
- Frankenstein's monster
- Frankincense and myrrh
- Fraud or defraud
- Fraught
- Free rein vs. free reign
- Freegan and freeganism
- Freeze vs frieze
- French accent marks
- French alphabet pronunciation
- French days and months
- French definite articles
- French greetings and salutations
- French indefinite articles
- French noun gender
- French numbers
- French partitive article
- Frenemy
- Freshwater vs. fresh water
- Freudian slip
- Friable vs fryable
- Friar vs fryer
- Friendsgiving
- Fringe benefit
- Fritter away
- Frivolity vs. frivolousness
- Frogmarch or frog-march
- From pillar to post
- From soup to nuts
- From the get-go
- Fuddle
- Fueled/fueling vs. fuelled/fuelling
- Fulfil vs. fulfill
- Full stop vs. period
- Full-fledged, fully fledged
- Fulminate vs culminate
- Fulsome
- Funereal
- Fungi vs. funguses
- Funk
- Funner, funnest
- Fur vs fir
- Furlough
- Furor vs. furore
- Fusillade vs fuselage
- Fusion vs confusion
- Futz vs putz
G
- Gadfly
- Gaff vs. gaffe
- Gage, gauge, and gouge
- Gaiety or mirth
- Gainsay
- Gait vs gate
- Gaiter vs gator
- Gallimaufry
- Gallon vs galleon
- Gallop vs Gallup
- Galore
- Galumph
- Gambit
- Gambol vs. gamble
- Game changer
- Gamut vs gambit
- Gantlet vs. gauntlet
- Gaol vs. jail
- Gargle vs. gurgle
- Gargoyle or grotesque
- Garner vs garnish
- Garnish vs garnishee
- Garret vs garrote
- Garrote, garrotte, or garotte
- Garter snake
- Gases vs. gasses
- Gaslighting
- Gastropub
- Gatecrasher
- Gaudy vs. gawdy
- Gavel-to-gavel
- Gaveled vs. gavelled
- Gay
- Gel vs jell
- Gemology vs gemmology
- Gender vs engender
- Gender vs. sex
- Generalize vs generalise
- Genericide
- Genes vs jeans
- Gentle vs genteel
- Gentrification
- Geocaching
- Geographic vs geographical
- German vs germane
- Geronimo!
- Gerrymander
- Gerunds
- Gestalt
- Gesture vs jester
- Gesundheit
- Get a foot in the door
- Get down to brass tacks
- Get one's dander up or get one's dandruff up
- Get one's ducks in a row and have one's ducks in a row
- Get religion
- Get someone’s goat
- Get the ball rolling and start the ball rolling
- Get the skinny
- Get together vs get-together
- Getaway vs get away
- Ghost in the machine
- Ghost vs ghoul
- Gibberish
- Gibe, jibe, jive
- GIF
- Gift (as a verb)
- Gild the lily
- Gild vs. guild
- Gilt vs guilt
- Gimlet eye and gimlet cocktail
- Gimme
- Gin something up
- Ginormous
- Gist vs. jist
- Git-go
- Give a wide berth
- Give no quarter
- Give one's eye teeth
- Give up the ghost
- Glad-hand
- Glamour vs. glamor
- Glamping
- Glass ceiling
- Gleam vs glean
- Glib
- Glitch
- Glom onto
- Gloves are off, take the gloves off
- Go big or go home
- Go down a treat
- Go for broke
- Go for the jugular
- Go haywire
- Go off half-cocked and go off at half-cock
- Go the extra mile
- Go to ground
- Go to hell in a handbasket
- Gobbledygook
- Gobsmacked
- Gobsmacked
- God (capitalization)
- Godspeed
- Goes without saying
- Gofer vs. gopher
- Going against the grain
- Going bananas
- Going Dutch and Dutch treat
- Going to rack and ruin
- Going to the dogs
- Going viral
- Gold-digger
- Goldbrick
- Golden ticket
- Gonna
- Goober
- Good Samaritan
- Good vs well
- Goodly
- Goody two shoes
- Google vs google
- Goose that lays the golden eggs
- Goose-step
- Goosebumps, goose pimples and gooseflesh
- Gorilla vs. guerrilla
- Gorp
- Got vs. gotten
- Gourmet vs gourmand
- Governance vs. government
- Graffiti
- Grammar Monster.com
- Grammar Ninja
- Grammar vs. usage
- Grammarist
- Grammarly Review 2017 - Does it do all it claims to do?
- Grammarphobia
- Grand slam
- Grandfather (as a verb)
- Grasping at straws or clutching at straws
- Grassroots vs grass roots
- Grate vs great
- Grateful vs. gratified
- Gratis, gratuitous and gratuity
- Graveyard shift
- Gravid vs grave
- Gravity vs levity
- Gravy train
- Gray vs. grey
- Great Scott!
- Green around the gills and green about the gills
- Green thumb and green fingers
- Greenhorn vs tinhorn
- Gregarious vs garrulous
- Grenadine vs grenade
- Grieve vs aggrieve
- Grieve vs greave
- Grill vs. grille
- Grin like a Cheshire cat
- Grinch
- Grinded
- Grip vs grippe
- Grisly vs. grizzly
- Groan vs grown
- Grok
- Gross vs net
- Ground zero
- Groupthink
- Grub
- Grudge
- Gruel vs grueling
- Guarantee vs guaranty
- Guessed vs guest
- Guesstimate
- Guise vs guys
- Gumption
- Gun-shy
- Gung-ho
- Gunwale and gunnel
- Guyline vs guideline
- Gymnasia vs. gymnasiums
H
- Habeas corpus
- Habit vs habitat
- Hail Mary play or Hail Mary pass
- Hail vs. hale
- Hair of the dog
- Hair vs hare
- Hair's breadth (hare's breath)
- Hairbrained vs. harebrained
- Hairy vs. harry
- Halcyon
- Half-baked
- Half-mast vs. half-staff
- Halfhearted and half-hearted
- Halitosis
- Hall vs haul
- Hallow vs. hollow
- Halloween or Hallowe'en
- Halve
- Halve vs have
- Hand over fist
- Hand-me-down
- Hand-wash
- Handful, handfuls
- Handicap vs. handicapped
- Handle with kid gloves
- Hands down
- Hands on or hands-on
- Hang on like grim death and hang on for grim death
- Hangar vs. hanger
- Hangdog
- Hanged vs. hung
- Hangry
- Hanker vs hunker
- Hanky-panky
- Hanukkah or Chanukah
- Happenstance
- Happy camper
- Happy median or happy medium
- Hara-kiri
- Harbinger
- Harbor vs. harbour
- Hardy vs. hearty
- Hare vs. rabbit
- Hark, harken, and hearken
- Harridan and harpy
- Hart vs heart
- Hash out, thrash out
- Hashtag
- Hat trick
- Hate-watch
- Hatemonger and hate-mongering
- Haughty vs hottie
- Have a bee in one's bonnet
- Have a cow and have kittens
- Have a field day
- Have an ax to grind
- Have one's ears pinned back vs pin one's ears back
- Have someone's number and I've got your number
- Have your cake and eat it too
- Hawk vs. hock
- Hay vs hey
- Hay vs straw
- Haymaker
- Head over heels
- Heads or tails and can't make heads or tails
- Heads up
- Headwind
- Heal vs. heel (and bring to heel)
- Healthcare vs. health care
- Healthful vs. healthy
- Hear through the grapevine, bush telegraph or jungle telegraph
- Hear vs listen
- Hear, hear vs. here, here
- Heard vs herd
- Heavens to Murgatroyd
- Hector
- Heebie-jeebies
- Heighth
- Hell for leather and hell-bent
- Helpless vs hapless
- Helter skelter or helter-skelter
- Hem and haw or hum and haw
- Hence
- Henpeck
- Herbivorous vs herbaceous
- Heretofore or hitherto
- Heroin vs. heroine
- Heterogeneous vs. heterogenous
- Heterometric
- Hew vs. hue
- Heyday
- Hi vs high
- Hie
- Hieratic
- Hieroglyph vs hierograph
- High five
- High on the hog
- High-handed
- Higher vs hire
- Highfalutin
- Hijinks or high jinks
- Himself vs hisself
- Hindsight is 20/20 and 20/20 hindsight
- Hinky
- Hippocratic vs hypocritical
- Hippogriff or griffin
- Hippopotami, hippopotamuses, hippos
- Historic vs. historical
- Histrionic, histrionics
- Hit a brick wall vs hit the wall
- Hit it off
- Hit pay dirt
- Hit the bricks
- Hit the ground running
- Hit the hay and hit the sack
- Hoar vs whore
- Hoard vs. horde
- Hoarse vs horse
- Hoax
- Hobo, tramp, bum, or gutter punk
- Hobson's choice
- Hocus-pocus
- Hodgepodge vs hotchpotch
- Hogwash
- Hoi polloi
- Hokey-pokey, hokey-cokey and hokey-tokey
- Hold sway
- Hold your horses
- Hole vs whole
- Holey vs. holy
- Holier-than-thou
- Holly vs holy
- Holy vs wholly
- Home in vs horn in
- Home in vs. hone in
- Home school vs. homeschool (vs. home-school)
- Homely vs. homey
- Homily vs sermon
- Homo sapiens
- Homogenous vs. homogeneous
- Homonym
- Honcho
- Honeymoon
- Honor among thieves and no honor among thieves
- Honor vs. honour
- Hoodwink
- Hoopla
- Hoosegow
- Hootenanny
- Hoover vs. vacuum
- Hooves or hoofs
- Hope or hopes
- Hoping vs hopping
- Horn of plenty and cornucopia
- Horse of a different color and horse of another color
- Horsey, horsy, horsie
- Horticulturist vs arborist
- Hosanna
- Hot button
- Hot mess
- Hot potato
- Hot spot or hotspot
- Houndstooth
- Hour vs our
- House of cards
- How's it going
- Hubris
- Hue and cry
- Hullabaloo
- Human vs humane
- Humblebrag
- Humdinger
- Humongous
- Humor vs. humour
- Humorousness
- Hump day
- Humus vs. hummus
- Hunt-and-peck
- Hunter-gatherer
- Hurdle vs. hurtle
- Hurrah, hooray, hurray
- Hurricane, typhoon and cyclone
- Hush money
- Hush puppy, hushpuppy or hush-puppy
- Hustle and side hustle
- Hybrid vs highbred
- Hygge
- Hyper- vs hypo-
- Hyphen
- Hyphen, en dash or em dash
I
- Ibid vs idem
- Ice tea vs. iced tea
- Icing on the cake
- Iconoclast vs heretic
- Idea vs. ideal
- Ideation vs idea
- Ideogram
- Ideologue
- Ides of March
- Idiom Hunt
- Idiom vs colloquialism
- Idiot savant or savant syndrome
- Idle, idol, idyll
- If it ain't broke don't fix it
- If need be or if needs be
- If the shoe fits and if the cap fits
- If vs whether
- If you can't beat them, join them
- If you can't stand the heat get out of the kitchen
- If you will
- Ignominious vs ignoble
- Ignoramus
- Ilk
- Illegible vs. unreadable
- Imaginary or imaginative
- Imagism
- Imbibe vs imbue
- Imbroglio
- IMHO
- Imitate vs emulate
- Imitate vs intimate
- Imitate vs intimidate
- Immaculate Conception vs. virgin birth
- Immolate vs emulate
- Immunity vs. impunity
- Impactful
- Impair vs impede
- Impassable vs. impassible
- Impassive vs. passive
- Impecunious and pecunious
- Impending vs. pending
- Impends vs impinge
- Imperial vs empirical
- Imperial vs empyreal
- Imperious vs. impervious
- Impinge vs. infringe
- Implosion vs explosion
- Imply vs. infer
- Imposter vs. impostor
- Impractical vs impracticable
- Imprecation vs implication
- Impromptu or improvised
- Improvise vs. improvize
- Impudent vs imprudent
- Impugn vs. impute
- In a jiffy
- In a manner of speaking
- In a New York Minute
- In a nutshell
- In a pickle
- In due course or in due time
- In excess of
- In kind
- In loco parentis
- In medias res
- In over one's head or over one's head
- In point of fact or in fact or as a matter of fact
- In situ
- In terms of
- In the affirmative
- In the ballpark and hit one out of the ballpark
- In the cards and on the cards
- In the course of
- In the doldrums
- In the hopper
- In the midst of
- In the midst vs in the mist
- In the offing
- In the pink
- In the process of
- In the red and in the black
- In the throes of
- In toto
- In two shakes of a lamb's tail
- In vitro
- Inalienable vs. unalienable
- Incarnation vs incarceration
- Incase or encase
- Incentivize, incent
- Incidence vs. incidents
- Incipient or inchoate
- Incipient vs. insipient (vs. insipid)
- Incite vs insight
- Inclement vs. inclimate
- Include, exclude or occlude
- Incommunicado
- Incomparable vs. uncomparable
- Incomprehensive or incomprehensible
- Incredible vs. incredulous
- Incubus, succubus
- Inculcate
- Indefatigable and defatigable
- Indefinite articles
- Indemnity and contribution
- Indeterminate vs indeterminable
- Indexes vs. indices
- Indian corn
- Indian giver
- Indian summer
- Indict vs indite
- Indiscriminate vs undiscriminating
- Indolence vs insolence
- Indubitably vs undoubtedly
- Inequality vs. inequity
- Inequity vs. iniquity
- Inexplicable vs. unexplainable
- Infect vs. infest
- Infectious vs contagious
- Inference vs interference
- Inflict vs inflect
- Infomercial
- Infraction vs infarction
- Infuse vs suffuse
- Ingenious vs. ingenuous
- Ingrate vs ingratiate
- Inhabit vs habituate
- Inherent vs inherit
- Innate vs enate
- Innocuous vs inoculate
- Inpatient or outpatient
- Inroad vs inroads
- Inside baseball
- Insidious vs invidious
- Insofar (in so far)
- Insolent vs insolvent
- Insolent vs insulate
- Installation vs. installment
- Installment vs. instalment
- Instantly vs. instantaneously
- Instigate vs incite
- Instigate vs investigate
- Instill vs install
- Instinctive vs. instinctual
- Intact
- Intellectual property
- Inter-, intra-
- Intercourse
- Interjections
- Interment vs. internment
- Intermural, intramural and extramural
- Intern vs inter
- Internal vs eternal
- Internal vs infernal
- Internet (capitalization)
- Internet of things
- Interpretative vs. interpretive
- Interrobang and interabang
- Interview with Abed Elmansur
- Interview with Arthur Plotnik
- Interview with Bethany Keeley
- Interview with Betty Birner
- Interview with Bill Walsh
- Interview with Blair Bolles
- Interview with Constance Hale
- Interview with Craig Silverman
- Interview with Gretchen McCulloch
- Interview with James Harbeck
- Interview with John McIntrye
- Interview with Jonathon Owen
- Interview with Lisa McLendon
- Interview with Merrill Perlman
- Interview with Mignon Fogarty
- Interview with Pat O'Conner
- Interview with Peter Harvey
- Interview with Stan Carey
- Interview with Stephen Dodson
- Inure vs enure
- Invaluable vs. valuable
- Inveigh vs inveigle
- Invention vs intervention
- Inveterate vs invertebrate
- Inviolable vs inviolate
- Invite (as a noun)
- Ipso facto
- Irish twins
- Irk
- Ironic
- Ironical
- Irregardless
- Irregular plural nouns
- Isometric
- It ain't over till the fat lady sings
- It takes two to tango
- It's Greek to me and it's all Greek to me
- It's the thought that counts
- Italics (when to italicize)
- Itchy feet
- Iteration
- Its vs. it's
- Ivory tower
- Ivy League
J
- Jack-in-the-box
- Jack-o’-lantern and Halloween lantern
- Jackalope
- Jackanapes
- Jackpot
- Jaded
- Jalousie window vs louvre window
- Jam vs. jamb
- Janus-faced
- Jaundiced eye
- Jaywalking
- Je ne sais quoi
- Jealousy vs envy
- Jejune
- Jejune
- Jeremiad
- Jersey vs guernsey
- Jet lag
- Jewel vs joule
- Jewelry vs. jewellery
- Jig vs gig
- Jiggery-pokery
- Jilt vs gilt
- Jingle vs jangle
- Jingoism
- Jinx
- Jitney
- John Doe, Joe Bloggs and Fred Nerk
- John Hancock and John Henry
- Johnny-on-the-spot
- Joie de vivre
- Joined at the hip and attached at the hip
- Jolly Roger
- Jones
- Joshing
- Jot or tittle
- Joyful and joyous
- Judgment vs. judgement
- Judicial vs. judicious
- Juggalo
- Juggernaut
- Jump or climb on the bandwagon
- Jump the gun
- Jump the shark
- Junction vs. juncture
- Junkie vs. junky
- Jury-rig, jerry-rig, jerry-built
- Just deserts vs. just desserts
- Juvenile vs juvenal
- Juxtapose
K
- K-pop
- Kafkaesque
- Kakistocracy
- Kaleidoscope
- Kangaroo court
- Kaput
- Katy bar the door
- Keep an ear to the ground
- Keep it under your hat
- Keep someone posted
- Keep your eyes peeled and keep your eyes skinned
- Keep your shirt on and keep your hair on
- Keeping up with the Joneses
- Kerfuffle vs brouhaha
- Kernel vs colonel
- Ketchup, catsup, catchup
- Kibosh
- Kick off vs. kickoff (vs. kick-off)
- Kick over the traces
- Kick the can down the road
- Kick-start
- Kilroy was here
- Kin vs ken
- King of the hill and king of the castle
- King's X
- Kiss of death
- Kith and kin
- Kleenex vs tissue
- Kludge
- Klutz
- Knap vs nap
- Knave vs nave
- Knee-high to a grasshopper
- Knee-jerk, kneejerk
- Kneeled vs knelt
- Knew vs new
- Knickers vs nickers
- Knight vs night
- Knighted vs benighted
- Knit vs nit
- Knit vs. knitted
- Knock on wood and touch wood
- Knock one's socks off
- Knock up
- Knocked for a loop and thrown for a loop
- Knot, nought, naught or not
- Know vs no
- Know where the bodies are buried
- Know which side your bread is buttered on
- Knuckle down and buckle down
- Knuckle under vs knuckle down
- Koan vs cone
- Kowtow
- Kryptonite
- Kudos
L
- L'état, c'est moi
- La dolce vita
- Labeled vs. labelled
- Labor vs. labour
- Lackadaisical
- Ladybug and ladybird
- Lagniappe
- Lain vs lane
- Lair vs layer
- Laird vs lord
- Laissez-faire
- Lambast vs. lambaste
- Lambaste
- Lame duck
- Landlubber
- Lanyard
- Laps vs lapse
- LARP
- Lasagna vs. lasagne
- Lassitude, lethargy and languor
- Last names (plurals and possessives)
- Last-ditch
- Latchkey kid and latchkey child
- Later vs latter
- Latitude vs longitude
- Latte art
- Latter vs ladder
- Laudable vs. laudatory
- Laughing stock
- Laundry list
- Lava vs magma
- Lay of the land or lie of the land
- Lay out vs. layout
- Lay vs. lie
- Lazy Susan
- Leach vs leech
- Lead vs. lede
- Lead-pipe cinch
- Leak vs leek
- Lean in
- Lean vs lien
- Leaned or leant
- Leap year
- Leaped vs. leapt
- Learn the ropes and know the ropes
- Learned vs. learnt
- Learnings
- Leave someone holding the bag
- Led vs. lead
- Leery vs leary
- Leet, leetspeak and 1337
- Leeway
- Leftover vs. left over
- Legal tender
- Legal vs legit
- Legislator vs legislature
- Legitimate vs legitimitize
- Lei
- Lend vs. loan
- Lended vs. lent
- Lentil vs lintel
- Leotard vs tights
- Lessen vs lesson
- Lesser or lessor
- Lest
- Let bygone be bygones
- Let one's hair down
- Let sleeping dogs lie
- Let's vs lets
- Letter names
- Levee vs. levy
- Level playing field and level the playing field
- Leviathan
- Liable vs libel
- Liar vs. lier
- Libel vs. slander
- Library Spot.com
- Licence vs. license
- Licker vs liquor
- Lickety-split
- Licorice vs. liquorice
- Lie or lye
- Lieutenant
- Lifetime or life time
- Light vs. lite
- Lighted vs. lit
- Lightening vs. lightning
- Likable vs. likeable
- Like a bull in a china shop
- Like a bump on a log
- Like gangbusters
- Like taking candy from a baby
- Lilliputian
- Limbo
- Limelight vs spotlight
- Linchpin vs. lynchpin
- Lion's share
- Lip-sync and lip-synch
- Lipid vs limpid
- Liquor vs liqueur
- Listserv
- Liter or litre vs litter
- Liter vs. litre
- Literally vs. figuratively
- Litmus test
- Little to no or little to none
- Live off the fat of the land
- Liveable or livable
- Living the life of Riley
- Llama vs lama
- Lo, lo and behold
- Load vs lode
- Loath vs. loathe (vs. loth)
- Locavore
- Lock out vs lockout
- Lock, stock and barrel
- Lodestar
- Log in vs. log on
- Log in vs. login
- Logo
- Lonely vs. lonesome
- Long in the tooth
- Long johns vs union suit and combination suit
- Long pig
- Longetivity vs. longevity
- Look out vs. lookout (vs. look-out)
- Loonie or loony
- Loop de loop or loop the loop
- Loop vs loupe
- Loophole
- Loose vs. lose
- Loot vs lute
- Loquacious
- Lorem Ipsum
- Lorry
- Lose face and save face
- Lose one's marbles
- Lose the plot
- Lothario
- Lots of vs a lot of
- Lovable vs. loveable
- Low, lo or lowe
- Low-hanging fruit
- Lowlife
- Lucid vs lucent
- Luddite
- Lukewarm
- Lumber vs lumbar
- Luminary vs luminaria
- Lustful vs. lusty
- Luxuriant vs. luxurious
- Lyme disease vs lime disease
M
- Macabre
- Macaron vs. macaroon
- MacGyver
- Mach vs mock
- Machiavellian
- Machine gun vs. machine-gun
- Macintosh, mackintosh, McIntosh
- Mad as a hatter
- Maddening vs. madding
- Magic bullet and silver bullet
- Magical realism
- Magnate vs. magnet
- Magnum opus
- Mail vs male
- Main, mane and Maine
- Maize vs maze
- Make a clean breast of it and come clean
- Make do vs. make due
- Make ends meet and make both ends meet
- Make hay
- Make no bones about it
- Makeup, make-up or make up
- Malarkey
- Maleficent vs. malevolent
- Malfeasance, misfeasance and nonfeasance
- Mall vs maul
- Malware vs ransomware
- Man's best friend
- Mancession
- Maneuver vs. manoeuvre
- Manga vs anime
- Manic vs maniac
- Manner vs. manor
- Mansplain
- Manspreading
- Mantel vs. mantle
- Many happy returns
- Many vs. much
- Mare vs mayor
- Marginalize or marginalise vs minimize or minimise
- Marie Nuzzi's Esl Connection
- Marinade vs. marinate
- Mark's ESL World
- Marquee vs marquis
- Marry vs. merry
- Marsala vs masala
- Marshal vs. martial
- Martin vs marten
- Mary Sue
- Massage vs message
- Masterful vs. masterly
- Materiel vs. material
- Math vs. maths
- Matriculate vs graduate
- Matrix
- Matter of fact or matter-of-fact
- Matter of fact vs fact of the matter
- Maudlin vs modeling or modelling
- Maul vs. mull
- Maundy Thursday
- Maverick
- Maxima vs. maximums
- Maximise or maximize
- May be or maybe
- Mayhap or mishap or snafu
- Mayonnaise vs. mayonaise
- McGuffin
- Mcjob
- Mea culpa
- Meager vs. meagre
- Mealy-mouthed
- Mean vs mien
- Means
- Meat, meet or mete
- Medal, meddle, metal, mettle
- Media vs. mediums
- Mediator vs. moderator
- Meeple
- Melted vs. molten
- Meme
- Memento mori
- Mendacity vs mendicity
- Mensch
- Meretricious vs meritorious
- Meritorious vs maritorious
- Merry Christmas vs Happy Christmas
- MES Games
- Meta
- Metaphor
- Metaphoric vs. metaphorical
- Meteoroid, meteor, meteorite (and meteoric)
- Meter vs. metre
- Methinks
- Mexican standoff
- MIA
- Mic drop
- Mic vs. mike
- Mice vs. mouses
- Mickey Finn and mickey
- Micro- vs macro-
- Microaggression
- Microfinance, microcredit and microloan
- Midrift (midriff)
- Might as well
- Might vs mite
- Milieu
- Militant or terrorist
- Militate or mitigate
- Millennia vs millenniums
- Milquetoast vs milktoast
- Mince vs mints
- Mind over matter
- Mind your own beeswax
- Miner vs minor
- Minima vs. minimums
- Minimize vs minimise
- Minimum vs minimal
- Minks vs. minx
- Mint condition
- Minuet vs minute
- Minuscule vs. miniscule
- Minutia, minutiae
- Mirandize
- Mischievous vs. mischievious
- Misery loves company
- Misinformed vs. uninformed
- Misnomer
- Misogyny and misandry
- Misology vs mixology
- Missed vs mist
- Misspell
- Mixtape
- Moat vs mote
- Mob justice and mob rule
- Mob or demob
- Mobilize vs mobilise
- Mode vs mowed
- Modeling vs. modelling
- Modern
- Modus operandi (m.o, MO)
- Mogul
- Mojo
- Mold vs. mould
- Mollusc vs. mollusk
- Mollycoddle
- Molt vs. moult
- Mom vs mom
- Momager
- Momentarily
- Monday morning quarterback and armchair quarterback
- Monetize vs demonetize
- Money-grabbing vs. money-grubbing
- Monied vs. Moneyed
- Monkey on one's back
- Montage
- Moonlight
- Moonshine
- Moose vs mousse
- Moose vs. mooses
- Moot vs. mute
- Moral vs morale
- Moratorium
- Morays vs. mores
- Morbid vs moribund
- More bang for one's buck and bigger bang for one's buck
- More than one way to skin a cat
- More vs moor
- Moreso
- Moribund
- Morning vs mourning
- Mortar board
- Mothball
- Mother lode
- Motive vs motif
- Mouse and CAT
- Moustache vs. mustache (vs. mustachio)
- Mouthfuls
- Movable feast
- Movable vs. moveable
- Mowed vs. mown
- Mr., Mrs., Ms. and Miss
- Much vaunted
- Muchly
- Muckamuck, mucky-muck and muckety-muck
- Muckraking
- Mucous vs. mucus
- Multitask
- Mum's the word
- Mumbo jumbo
- Murderers' row
- Murphy's Law, Sod's Law and Finagle's Law
- Muscle vs mussel
- Must of (must've)
- Mutually assured destruction or mutual assured destruction
- Mutually exclusive
- Muumuu
- My English Grammar.com
- Myriad
N
- Namby-pamby
- Namesake
- Nano-
- Nary a
- Nascent
- Nativity
- Naught vs. nought
- Nauseating vs. nauseous
- Naval vs. navel
- Navel-gazing
- Ne'er-do-well
- Neandertal vs. neanderthal
- Nebbish
- Nebula vs nebulous
- Necessity is the mother of invention
- Neck and neck
- Necropsy and autopsy
- Necrosis
- Need vs knead
- Needle vs nettle
- Nefarious
- Negative prefixes
- Neighbor vs. neighbour
- Nemesis
- Nepotism
- Nerd, dork or geek
- Nest egg
- Net neutrality
- Neutralise vs neutralize
- Never mind vs nevermind
- New vs gnu
- Newfangled
- News
- NGO vs GMO
- Nib vs nub
- Nice vs gneiss
- Nickle-and-dime
- Nickname
- Nicks vs nix
- Niggle
- Night owl or early bird
- Nimby, nimbyism
- Nimrod
- Nip in the bud
- Nitpick
- Nitpick
- Nitty-gritty
- No good deed goes unpunished
- No harm no foul
- No holds barred
- No ifs, ands, or buts
- No love lost
- No man is an island
- No man's land
- No one vs. noone (vs. no-one)
- No pain, no gain vs no pain, no game
- No-brainer
- Noble vs ignoble
- Noblesse oblige
- Nock vs knock
- Nocturnal vs diurnal
- Noel or nowel
- Noisome vs noisy
- Nomenclature
- Non sequitur
- None are or none is
- Nonfinite verbs
- Nonplussed
- Nonprofit vs. not-for-profit (vs. non-profit)
- Nonstarter
- Normalcy vs. normality
- Nosy Parker
- Not all it's cracked up to be
- Not by a long shot and not by a long chalk
- Not hardly
- Not one’s cup of tea
- Not playing with a full deck
- Not un-
- Not worth a plugged nickel and not worth a plug nickel
- Nothing to sneeze at and not to be sneezed at
- Notwithstanding
- Nouns
- Nouns as adjectives
- Nowadays, anymore, or any more
- Nullify
- Number vs numeral
- Numerals
- Numinous vs luminous
- Nun vs none
- Nunchucks
- Nutriment or nutrition
O
- O vs. oh
- Oar, ore and or
- Oases
- Object lesson
- Objects
- Obliged vs. obligated
- Oblique
- Obsequious
- Observance vs. observation
- Obsolescent vs. obsolete
- Obstreperous
- Ocher vs. ochre
- Octopi vs. octopuses
- Ode vs owed
- Odor vs. odour
- Oeuvre
- Off of
- Off one’s rocker and off one’s trolley
- Off the cuff
- Off the grid or off-grid
- Off the record vs not for attribution
- Off-kilter and out of kilter
- Offal vs awful
- Offence vs. offense
- Offhand
- Oftentimes
- Oh well
- OK vs. okay
- Old as Methuselah
- Old chestnut
- Old Glory
- Old hat
- Old wives' tale vs old wise tale
- Old-fashioned or old fashion
- Oldie but goodie
- Olfactory vs old factory
- Oligarchy vs monarchy
- Olive branch
- Ombré ombre or hombre
- Omelet vs. omelette
- Omnibus vs ombudsman
- On a lark
- On a shoestring and shoestring budget
- On a wing and a prayer
- On accident vs by accident
- On cloud nine
- On fleek
- On one's high horse
- On pins and needles
- On steroids
- On tenterhooks
- On the back foot
- On the ball
- On the bubble
- On the contrary
- On the fritz
- On the lam
- On the q.t.
- On the ropes
- On the spur of the moment
- On the stump and stump speech
- On the up and up
- On the wagon, off the wagon
- On the wrong foot and on the right foot
- On your mark, get set, go! and ready, set, go!
- Onboard vs. on board
- Once bitten, twice shy
- Once in a blue moon
- Once in a lifetime vs once-in-a-lifetime
- One and the same, one in the same
- One fell swoop
- One for the money, two for the show
- One's name is mud
- One-hit wonder
- One-horse town
- One-time vs. onetime
- One-trick pony
- One-upmanship
- Oneself vs. one's self
- Online vs. on-line
- Onomatopoeia
- Onus
- Oompa Loompa
- Op-ed
- Operationalise or operationalize
- Opossum vs. possum
- Oppress, repress, suppress
- Oracle vs auricle
- Oral vs. verbal
- Ordinance vs. ordnance
- Organise vs. organize
- Orientate
- Origin or origins
- Ornery
- Orthopedic vs. orthopaedic
- Ought vs aught
- Ouster
- Out and out
- Out of one's league
- Out of pocket
- Out of sorts
- Out of the blue vs out of the woodwork
- Out of whole cloth
- Outside of
- Outsource
- Over a barrel
- Over the hill
- Over the hump
- Over- and under- (prefixes)
- Overbilled vs overbuild
- Overdo vs. overdue
- Overlook vs look over
- Overly
- Overnight vs. over night
- Overrate vs overate
- Oversee vs overlook
- Oversees vs overseas
- Overtake, take over and takeover
- Overthink vs think over
- Overtones vs. undertones
- Oxymoron
- Oxymorons
P
- p.d.q.
- Packed vs pact
- Paddy wagon
- Paean, paeon, peon
- Paid vs. payed
- Pail vs pale
- Pain vs pane
- Paint the town red and paint the town
- Pair vs. pare vs. pear
- Pajamas vs. pyjamas
- Palate, palette, pallet
- Pale in comparison
- Palindrome (poetry)
- Pall vs. pallor
- Palpable vs palatable
- Pan out
- Pander vs ponder
- Panhandle
- Paper tiger
- Par excellence
- Parade float
- Parallel vs perpendicular
- Paralympics
- Paralyse vs. paralyze
- Parameter vs perimeter
- Paramount vs. tantamount
- Paraphernalia
- Pardon my French and excuse my French
- Parentheses (round brackets)
- Parentheses vs brackets
- Parish vs perish
- Parkour
- Parlay vs. parley
- Parlor or parlour
- Parody vs parity
- Parol vs parole
- Parricide vs. patricide
- Parsimony
- Part and parcel
- Participial prepositions
- Participles
- Parting shot
- Pass muster
- Pass muster vs pass mustard
- Pass the buck, the buck stops
- Pass the torch and hand on the torch
- Passable or passible
- Passed vs. past
- Passerbys or passersby
- Passing strange
- Past master
- Paste vs paced
- Pasteurize vs pasteurise
- Pastiche vs pistachio
- Pastime vs past time
- Paten vs patten
- Patent leather
- Path of least resistance and line of least resistance.
- Pathetic vs apathetic
- Patience vs patients
- Patois
- Patriot
- Patriotism vs nationalism
- Patsy
- Patsy
- Paucity
- Pause vs paws
- Pay it forward
- Pay one's respects
- Pay the piper
- Pay through the nose
- Payback vs. pay back
- Peace of mind, piece of (one's) mind
- Peaceable vs. peaceful
- Peak vs. peek vs. pique
- Peal vs. peel
- Peanut gallery
- Pearl vs purl
- Pearls of wisdom
- Peccadillo
- Pecking order
- Peckish
- Pedal vs. peddle vs. petal
- Pediatric or paediatric
- Pediment vs impediment
- Peeping Tom
- Peer vs pier
- Pejorative
- Pell-mell
- Penal vs. penile
- Penchant vs pension
- Pendant vs. pendent
- Penny wise and pound foolish
- Penny-pinching
- Pentagon
- Penultimate
- People vs. persons
- Peplum vs pablum
- Per diem
- Per se
- Per vs purr
- Percent vs. per cent
- Perchance
- Peremptory vs pre-emptory
- Perfect English Grammar
- Perfect storm
- Perfunctory vs peremptory
- Period (full stop or full point)
- Periodic vs. periodical
- Peripatetic
- Perjury
- Perk vs perq
- Pernickety vs. persnickety
- Perpetrate vs perpetuate
- Perquisite vs. prerequisite (vs. requisite)
- Persecute vs. prosecute
- Persona non grata
- Personage vs parsonage
- Personal vs personable
- Personal vs personnel
- Personality vs personage vs persona
- Perspective vs. prospective
- Persuade vs dissuade
- Peruse
- Pervert vs subvert
- Pet peeve
- Pet vs. petted
- Peter out
- Petrifaction vs. petrification
- Petroglyph vs pictograph
- Pettifogger
- Petulant vs impetuous
- Pharaoh or Pharoah
- Phenomena, phenomenon
- Phial vs. vial (vs. vile)
- Philippic
- Phishing
- Phony vs. phoney
- Phosphene
- Phosphorous vs. phosphorus
- Photo shoot vs. photoshoot
- Photobomb
- Photogenic vs photographic
- Phrasal adjectives
- Phrasal prepositions
- Phrasal verbs
- Phrases
- Phubbing
- Pica vs pika
- Picaresque vs. picturesque
- Picayune
- Picks, pix or pyx
- Pickup vs. pick up (vs. pick-up)
- Pidgin vs pigeon
- Pie hole
- Pie in the sky
- Pie vs pi
- Piebald, skewbald, pinto or paint
- Piece of cake
- Piece vs peace
- Piecemeal
- Pied Piper
- Pig in a poke
- Pig Latin
- Piggy bank
- Piggyback
- Pin money
- Pincer vs. pincher
- Pink slip
- Pipe down and pipe up
- Pipe dream
- Piping hot
- Pipsqueak
- Pissant
- Pistol vs pistil
- Pitchblende
- Pitcher vs picture
- Pith vs pit
- Pithy
- Pixelated vs. pixilated
- Pièce de résistance
- Placate vs placket
- Place card vs placard
- Placebo vs nocebo
- Plain vs. plane
- Plainclothes
- Plaintiff vs defendant
- Plaintive vs plaintiff
- Plait vs plate
- Plantar vs planter
- Plaque vs plack
- Plateaus vs. plateaux
- Platypi vs platypuses
- Play by ear
- Play fast and loose
- Play gooseberry
- Play hardball
- Playwright vs. playwrite
- Pleaded vs. pled
- Please vs pleas
- Pleather and Naugahyde
- Plenary vs preliminary
- Plenitude vs. plentitude
- Plethora
- Pleural vs plural
- Plough vs. plow
- Plug-ugly vs pug-ugly
- Plum vs. plumb
- Plurals of nouns ending in 'Y'
- Plutocrat vs autocrat
- Podcast
- Podium vs lectern
- Poetic justice
- Pogrom vs genocide
- Point in time
- Point of no return
- Point of view, standpoint, viewpoint
- Point-blank
- Poisoning the well
- Poisonous vs venomous
- Poker face
- Pole vs poll
- Polemic vs. polemical
- Polite company and polite society
- Politics
- Polka dot
- Pollyanna
- Poly- vs mono-
- Polygamy vs. polygyny vs. polyandry
- Pomp and circumstance
- Pompom vs. pompon (vs. pom-pom etc.)
- Ponderous
- Pony up
- Ponzi scheme and Ponzi game
- Poo vs. pooh
- Poof, pouf or pouffe
- Pooh-bah or poobah
- Pooped
- Poor sport, sore loser and sore winner
- Pop one's clogs
- Popinjay
- Poppycock
- Populace vs. populous
- Porch vs veranda or verandah
- Pore over vs. pour over
- Pore, pour or poor
- Pork barrel
- Port vs. starboard
- Portend vs pretend
- Portend vs. portent
- Possibility vs probability
- Post-truth
- Poster child
- Postpositive adjectives
- Potato and potatoes, tomato and tomatoes
- Potentiality
- Potluck
- Potter's field
- POTUS
- Powwow
- Pox
- Practicable vs. practical
- Practical joke
- Practice vs. practise
- Pragmatism
- Pram, baby carriage and baby buggy
- Prank call or crank call
- Pray vs. prey
- Prebiotic vs probiotic
- Precede vs. proceed
- Precedence vs precedents
- Precipitate vs precipitous
- Precocious vs precious
- Predicate nominatives
- Predict vs predicate
- Predominantly and predominately
- Premier vs. premiere
- Preposition vs. proposition
- Prepositions
- Prescient vs present
- Prescribe vs. proscribe
- Present company excepted vs present company accepted
- Present progressive tense
- Preserve vs persevere
- President (capitalization)
- Press the flesh
- Presumptive vs. presumptuous
- Pretence vs. pretense
- Pretentious vs portentous
- Preternatural vs supernatural
- Preventative vs. preventive
- Previous vs. prior
- Pride vs pried
- Prima donna
- Primal scream
- Prime the pump
- Primrose path
- Principal vs. principle
- Prioritize vs prioritise
- Privacy policy
- Private eye and gumshoe
- Privatization vs nationalization
- Privy
- Proactive
- Probity vs improbity
- Problematic vs. problematical
- Procrastinate
- Prodigal and prodigy
- Prodigal son
- Prodigious vs prolific
- Profit vs prophet
- Progeny vs prodigy
- Program vs. programme
- Proliferate vs profligate
- Prom and The Proms
- Promise vs premise
- Promulgate vs propagate
- Prone, prostrate, supine
- Pronouns
- Proof by example
- Proof is in the pudding
- Prophecy vs. prophesy
- Propitiate vs expiate
- Proportional vs. proportionate
- Props
- Prorogue vs prolong
- Pros vs prose
- Prostate vs. prostrate
- Protagonist, antagonist
- Protean vs protein
- Protégé
- Proved vs. proven
- Proverb vs adage
- Proverbial vs figurative
- Providence vs province
- Province vs provenance
- Proviso
- Proximal vs proximate
- Psalter vs salter
- Pseudo
- Psych vs. psyche
- Psychiatry vs. psychology
- Psychopath vs. sociopath
- Pugnacious
- Pull out all the stops
- Pull rank
- Pull strings
- Pull the rug out from under
- Pulling one's leg
- Pullout, pull-out, pull out
- Punch list
- Punctilious vs punctual
- Pundit
- Pupal vs pupil
- Puppy love or poppy love
- Purple prose
- Purpose vs porpoise
- Purposely vs. purposefully
- Push someone's buttons
- Push the envelope
- Pusillanimous
- Put a damper on
- Put a flea in someone's ear vs put a bug in someone's ear
- Put on heirs or airs
- Put one's best foot forward
- Put one's cards on the table and lay one's cards on the table
- Put the cart before the horse
- Put though the wringer vs put through the ringer
- Put up your dukes
- Putative vs punitive
- Putrefaction
- Pyrrhic victory
Q
- Qua
- Quaff vs coif
- Qualitative vs. qualitive
- Qualitative, quantitative
- Quality time
- Qualm vs calm
- Quantitative vs. quantitive
- Quantum
- Quarts vs quartz
- Quash vs. squash
- Quasi
- Quay
- Quelch vs. squelch
- Query vs inquiry
- Question mark
- Quick entries: A
- Quick entries: B
- Quick entries: C
- Quick entries: D
- Quick entries: E
- Quick entries: F
- Quick entries: G
- Quick entries: H
- Quick entries: I
- Quick entries: J, K, L
- Quick entries: M
- Quick entries: N
- Quick entries: O
- Quick entries: P-Q
- Quick entries: R
- Quick entries: S
- Quick entries: T
- Quick entries: U-V
- Quick entries: W, X, Y, Z
- Quicksilver
- Quid pro quo
- Quince vs quints
- Quire vs choir
- Quisling
- Quiver vs quaver
- Quixotic
- Quo warranto
- Quotation marks
- Quote-unquote
R
- Rabble-rouser
- Rack one's brain
- Rack vs. wrack
- Racket vs. racquet
- Raconteur
- Radical
- Rail vs rale
- Rain, reign and rein
- Raining cats and dogs
- Raise Cain
- Raise vs rays
- Raise vs raze
- Raise vs rise
- Raison d'etre
- Rake over the coals and haul over the coals
- Rambunctious
- Ramshackle
- Rancor vs. rancour
- Random act of kindness
- Randomize vs randomise
- Rank and file
- Rappel vs. repel
- Rapt vs. wrapt
- Raring to
- Rat race
- Rational or rationale
- Ravaging vs. ravishing
- Raven vs ravenous
- Razzle-dazzle and razzmatazz
- Razzmatazz or razzamatazz
- Re-create vs. recreate
- Reactionary vs. reactive
- Read between the lines
- Read the riot act
- Real-time vs. real time
- Realise vs. realize
- Really Learn English
- Realty vs reality
- Reappropriate
- Rearranging the deck chairs on the Titanic
- Rebuke vs refute
- Rebus
- Rebut vs refute
- Recede vs reseed
- Receipt vs recipe
- Recent vs. resent
- Recognize vs recognise
- Reconnoiter
- Recur vs. reoccur
- Recuse vs excuse
- Red carpet
- Red herring
- Red tape
- Red vs read
- Red-letter day
- Redact vs retract
- Redneck vs hick vs hillbilly
- Redoubt
- Redress vs readdress
- Reed vs read
- Reek vs wreak
- Referendum
- Reforested wood
- Refugee vs immigrant
- Regard vs. regards
- Regift
- Regime vs. regimen
- Regimen vs regiment
- Regrettable vs. regretful
- Regulate vs relegate
- Reindeer or caribou
- Reinvent the wheel
- Rejig vs. rejigger
- Relative pronouns
- Relevance vs. relevancy
- Reluctant vs reticent
- Remunerate vs. renumerate
- Renascence and renaissance
- Rend or rent
- Renege vs rescind
- Repair vs reparation
- Repatriation vs reputation
- Repeal vs repeel
- Repel vs. repulse
- Repertoire or repertory
- Repetition vs repetitiveness
- Repetitive vs redundant
- Repudiate vs refute
- Repugnant vs pungent
- Repute vs refute
- Reputedly vs reportedly
- Requiem
- Resemble vs reassemble
- Resign vs re-sign
- Resilience vs. resiliency
- Resister vs resistor
- Resolve vs solve
- Respective, respectively
- Rest on one's laurels
- Rest vs wrest
- Restaurateur vs. restauranteur
- Restitution vs retribution
- Restive
- Restrict vs constrict
- Restrictive and nonrestrictive
- Retard
- Retch vs. wretch
- Retcon
- Retrograde vs anterograde or antegrade
- Retrospect vs introspect
- Reverent vs reverend
- Review vs. revue
- Rhetorical question
- Rhyme or reason
- Rhyme vs rime
- Ridded
- Ride on someone's coattails and coattail effect
- Ride roughshod and run roughshod
- Ride shotgun and call shotgun
- Rife vs. ripe
- Riff vs. rift
- Riffle vs rifle
- Riffraff
- Riffraff vs riprap
- Right off the bat
- Right, rite or write
- Right-of-way
- Right-side up
- Righten
- Rigmarole
- Rigor mortis
- Ring vs. wring
- Rings a bell
- Riposte vs repost
- Riptide, rip current or undertow
- Rise like a phoenix from the ashes
- Risky vs risqué
- Rite of passage
- Rivaled/rivaling vs. rivalled/rivalling
- Road kill or roadkill
- Road rage
- Road vs rode
- Roam vs Rome
- Rob Peter to pay Paul
- Robot, android or droid
- Rock 'n' roll, rock and roll, rock'n'roll, etc.
- Rogue vs. rouge
- Role vs. roll
- Rollout vs. roll out
- Rollover vs. roll over
- Roman-à-clef
- Roofs vs. rooves
- Rookie
- Roommate, room mate or room-mate
- Root vs. route vs. rout
- Rose-colored glasses
- Rot vs wrought
- Rotate or revolve
- Rotund vs rotunda
- Round robin
- Roux, rue or roué
- Rows vs rose
- Royal "we"
- RSVP
- Rubberneck
- Rubenesque
- Ruff vs rough
- Rule of thumb
- Rummy
- Rumor vs. rumour
- Run of the mill and run-of-the-mill
- Run rings around someone and run circles around someone
- Run the gamut vs run the gauntlet
- Run-on sentences
- Runaway vs. run away
- Rye vs wry
- Résumé
S
- Sabbatical vs sabbath
- Sac vs sack
- Saccharin vs. saccharine
- Sachet vs sashay
- Sackcloth and ashes
- Sacred cow
- Sacrilege, sacrilegious
- Sadism, masochism and sadomasochism
- Safe-deposit box
- Said
- Said the actress to the bishop
- Sail vs sale
- Salacious
- Salad days
- Salient vs salience
- Salt of the earth
- Saltwater vs. salt water
- Salubrious vs lugubrious
- Salvage vs selvage or selvedge
- Same difference
- Same old same old
- Samovar vs scimitar
- Sanatorium vs sanatarium
- Sanctimonious vs sanctify
- Sanction
- Sang froid
- Sang vs sung
- Sangfroid
- Sanguine vs exsanguinate
- Sanitise vs sanitize
- Sank vs. sunk
- Sans
- Sarcasm
- Sarcophagus
- Sarcophagus vs mausoleum
- Sari vs sorry
- Sartorial vs satirical
- Satire vs satyr
- Satisficing vs satisfying
- Savanna vs. savannah
- Savant vs servant
- Save something for a rainy day
- Saved by the bell
- Savior vs. saviour
- Savoir faire
- Savor vs saver
- Savvy
- Say cheese
- Say one's peace vs piece
- Say when
- Scam or sham
- Scared vs scarred
- Scarfs vs. scarves
- Scatological
- Scavenger hunt
- Scavenger, scavenge
- Sceptic vs. skeptic
- Schadenfreude
- Schadenfreude
- Schema or schematic
- Schizophrenia as an adjective
- Schmooze and shmooze
- Schmuck versus putz
- Scintilla
- Scion
- Scissors
- Scofflaw
- Scot-free
- SCOTUS
- Screed
- Screwball
- Scrimp vs skimp
- Scrip vs script
- Scrooge
- Scrumdiddlyumptious
- Scrummy
- Scuba
- Scuffle
- Scull vs skull
- Sculpture vs sculptor
- Scuttlebutt
- Sea change
- Seam vs seem
- Sear vs. seer vs. sere
- Seas, sees or seize
- Seasonable vs seasonal
- Seasons (capitalization)
- Secede vs. succeed
- Second that emotion or notion or motion
- Second wind
- Second-guess
- Secret Santa
- Secret vs. secretive
- Secular vs sacred
- Security blanket
- Sediment vs sentiment
- Sedimentary vs sedentary
- Sedition vs sedation
- See vs sea
- Seen vs scene
- Segue vs Segway
- Seldomly
- Self vs self
- Selfie
- Selling like hotcakes
- Semi-, hemi-, and demi-
- Semicolon
- Seminal
- Semper fidelis
- Sensational vs sensationalistic
- Sensual vs. sensuous
- Sentence-ending prepositions
- Sentences
- Sentience vs sapience
- Sentient
- Sentient vs sentiment
- Separate vs seperate
- Sepulcher, crypt, catacomb or mausoleum
- Sequacious
- Sequins vs sequence
- Seraphic
- Serf vs surf
- Series
- Serif vs seraph
- Serigraph vs lithograph
- Service (as a verb)
- Serviette or napkin
- Servitude vs certitude
- Set up vs. setup
- Sever vs severe
- Sew vs. sow
- Shaggy-dog story
- Shake a leg
- Shake one's head vs nod one's head
- Shall vs. will
- Shamble, shambolic
- Shame vs ashamed
- Shanghai (as a verb)
- Sharable vs. shareable
- Shard or sherd
- Share and share alike vs per stirpes
- Shat vs. shitted
- Shaved vs. shaven
- Shear vs. sheer
- Sheath vs. sheathe
- Shed vs. shedded
- Shelf vs. shelve
- Shell out
- Shellac, shellack
- Shenanigans
- Sherbert vs. sherbet
- Shill vs chill
- Shined vs. shone
- Shiplap
- Shiv
- Shoe vs shoo
- Shone vs shown
- Shoo-in
- Shoot oneself in the foot
- Shoot the breeze
- Shooting the messenger and don't shoot the messenger
- Shop till you drop
- Shopping cart or buggy
- Shore up
- Shore vs sure
- Short shrift
- Short shrift
- Shotgun vs rifle
- Shotgun wedding
- Should have, should've or should of
- Shoveled/shoveling vs. shovelled/shovelling
- Show of hands
- Show one's cards and tip one's hand
- Showboat
- Showrunner
- Shrinking violet
- Shriveled/shriveling vs. shrivelled/shrivelling
- Shtick
- Shutter vs. shudder
- Sic
- Sic semper tyrannis
- Sic vs. sick
- Side hustle
- Side vs sighed
- Sight vs. site
- Sign up vs signup
- Signet vs cygnet
- Silicon vs. silicone
- Silva vs silver
- Silver lining
- Silver-tongued
- Silviculture
- Simile
- Simpatico
- Since vs because
- Since, sense and cense
- Sine die
- Sine qua non
- Sing for one's supper
- Singly vs singularly
- Sink or Swim
- Sink vs sync
- Sisyphean, Promethean or Herculean
- Sit at the feet of someone
- Site vs cite
- Sitting duck
- Sitting in the catbird seat
- Six ways from Sunday
- Sizable or sizeable
- Skein vs scan
- Skeleton in the closet and skeleton in the cupboard
- Skid row vs skid road
- Skilful vs. skillful
- Skort
- Skulduggery
- Skunkworks
- Slam dunk
- Slap-happy
- Slave driver
- Slay vs sleigh
- Slayed or slew
- Sled, sledge, sleigh and toboggan
- Sledge vs sludge
- Sleight of hand
- Sleight vs slight
- Slipshod
- Slough vs slew
- Slow vs sloe
- Slumgullion and goulash
- Smack of
- Smarmy
- Smart alec and smart aleck
- Smartphone vs smart phone
- Smarty-pants and smarty-boots
- Smell a rat
- Smelled vs. smelt
- Smite, smote, smitten
- Smithereens
- Smoke and mirrors
- Smokey vs. smoky
- Smoking gun
- Smoothe, smoothen
- Smorgasbord
- Snake oil, snake-oil salesman
- Sneaked vs. snuck
- Snipe hunt
- Snitch
- Snobbery or snobbishness
- So to speak
- Soapbox
- Soar vs sore
- Soared vs sword
- Sob sister and sob story
- Soccer mom and hockey mom
- Social vs sociable
- Sojourn vs adjourn
- Solder vs soldier
- Soldiers, marines, airmen, sailors
- Sole vs soul
- Soliloquy vs monologue
- Solitaire and patience games
- Somber vs. sombre
- Some odd
- Some vs sum
- Some way vs. someway
- Somebody vs. someone
- Someday vs. some day
- Someplace vs. some place
- Somersault
- Something smells fishy
- Sometime vs. some time
- Sooner rather than later
- Sophistry
- Sorbet
- Sort of
- SOS and Mayday
- Sound bite
- Sound like a broken record
- Soup up
- Sow wild oats
- Spaces between sentences
- Spade vs spayed
- Spake
- Spanish fly
- Spartan
- Spat or spitted
- Spatter vs. splatter
- Speak now or forever hold your peace
- Speak of the devil
- Speak to
- Speak truth to power
- Speak with a forked tongue
- Spearhead
- Speciality vs. specialty
- Species
- Specious vs spurious
- Speck vs spec
- Specter vs. spectre
- Spectra vs. spectrums
- Sped vs. speeded
- Spelled vs. spelt
- Spelling bee
- Spendthrift
- Spic and span vs spick and span
- Spiel
- Spiffy
- Spill the beans
- Spilled vs. spilt
- Spin doctor
- Spinster
- Spit and image vs. spitting image
- Spite vs respite
- Split infinitives
- Split the difference
- Spoiled vs. spoilt
- Spoof
- Spoonerism vs malapropism
- Spoopy and creppy
- Spore vs spoor
- Spork
- Spouse vs espouse
- Spreaded
- Spruce up
- Spry
- Spur vs spurn
- Spur vs. spurn
- Squinch
- Stadia vs. stadiums
- Staff vs staph
- Staid vs stayed
- Stained glass
- Stair vs stare
- Stake vs steak
- Stalactite, stalagmite
- Stalking horse
- Stanch vs. staunch
- Stand alone vs standalone
- Stand up vs prop up
- Standby vs. stand by
- Stank, stunk
- Star-crossed
- Start from scratch
- Stat vs now
- State of the art
- Stationary vs. stationery
- Statue vs statute
- Status quo
- Statute of limitations
- Staycation
- Steal someone's thunder
- Steal vs steel
- STEM
- Stent vs stint
- Step vs steppe
- Stick to, stick by, or stick with
- Stick-in-the-mud
- Sticktoitiveness
- Stigma, stigmas or stigmata
- Stir-crazy
- Stock vs stalk
- Stock, shares
- Stockholm syndrome
- Stocking stuffer and stocking filler
- Stomping ground and stamping ground
- Stone cold and stone-cold
- Stonewall
- Stool pigeon
- Storey vs. story
- Straight from the horse's mouth
- Straight from the shoulder
- Straight vs. strait
- Strait-laced
- Straitjacket
- Stratagem vs. strategy
- Strategy vs tactic
- Straw man and man of straw
- Straw man fallacy
- Straw that broke the camel’s back and the last straw
- Strike while the iron is hot
- Striped/striping vs stripped/stripping
- Strived, striven, strove
- Stroller or pushchair
- Strop vs strap
- Stuffing vs dressing
- Stupefaction
- Sty vs stye
- Style vs stile
- Sub rosa vs sub-rosa
- Sub vs infra
- Subconscious vs. unconscious
- Subject to vs subjected to
- Subjects and predicates
- Subjugated vs subjected to
- Subjunctive mood
- Subordinating conjunctions
- Suborn
- Subpoena
- Substantial vs. substantive
- Subtext
- Subtle vs. subtil
- Succor or succour vs sucker
- Suede vs swayed
- Suffice it to say
- Suffixes
- Sugar daddy
- Sui generis
- Suit vs suite
- Suite vs sweet
- Sulfur vs. sulphur
- Sulk vs skulk
- Summa cum laude or magna cum laude
- Summary vs. summery
- Summons and summonses
- Sun vs son
- Sunday driver
- Sunday vs sundae
- Super vs supra
- Super vs ultra
- Supercilious
- Supermoon
- Supersede or supercede
- Superstorm
- Supply and demand
- Supposably
- Supposed to
- Surely vs surly
- Surge vs serge
- Surgeon vs sturgeon
- Surplus vs surplice
- Surrogacy
- Surveil
- Suspect, person of interest or perpetrator
- Sutler vs settler
- Svengali
- Swan song
- Swanning around and swanning about
- Swashbuckle
- Swatch vs swath
- Swath vs. swathe
- Swatting
- Sweat vs. sweated
- Sweeped or swept
- Sweet tooth
- Sword of Damocles
- Sycophant
- Symbol vs cymbal
- Symbolic vs symbiotic
- Synchronise or synchronize
- Synecdoche
- Synonyms
- Systematic vs systematical
- Systematic vs. systemic
T
- T-shirt, t-shirt, tee-shirt, tee shirt
- Tabula rasa
- Tacit vs taciturn
- Tack vs. tact
- Tacks vs tax
- Tad bit vs tidbit
- Tail vs. tale
- Tail wagging the dog
- Take a back seat
- Take a gander
- Take a rain check
- Take a shine to
- Take a toll and take its toll
- Take at face value
- Take for granted or take for granite
- Take over vs. takeover
- Take the bull by the horns and grab the bull by the horns
- Take the cake
- Take the Fifth and plead the Fifth
- Take the high road
- Take the mickey out of someone
- Take with a grain of salt and take with a pinch of salt
- Takeaway and takeout
- Taken aback
- Talk a blue streak and curse a blue streak
- Talk turkey
- Tamper vs temper
- Tanker vs tankard
- Taper vs tapir
- Tar and feather
- Tar baby
- Tariff
- Taro vs tarot
- Tartar or tartare
- Taser
- Tattletale vs telltale
- Taught vs taut
- Taupe vs tope
- Taut vs taunt
- Tautology
- Tea vs tee
- Teacher's pet
- Team vs teem
- Tear vs tare
- Teas vs tease
- Tease out
- Teeth vs. teethe
- Teetotaler, teetotaller
- Telegram vs. telegraph
- Tell it to the marines
- Temblor, tremblor or trembler
- Tempest in a teapot and storm in a teacup
- Temporal vs Templar
- Tempus fugit
- Tenant vs. tenet
- Tenure vs tenor
- Terminate
- Tern vs turn
- Terra firma
- Terrific vs terrifying
- Terroir and terror
- Terza rima
- Testament vs. testimony
- Tete-a-tete
- Textish
- Than vs. then
- Thanksgiving or Thanksgiving Day
- That or who
- That vs. which
- That which
- That's all she wrote
- The $64,000 question
- The apple of one's eye
- The be-all and end-all
- The birds and the bees
- The blind leading the blind
- The Bronx
- The die is cast
- The dogs of war
- The exception that proves the rule
- The face that launched a thousand ships
- The Grammar Casino
- The Grammar Gorillas
- The handwriting on the wall or the writing on the wall
- The jaws of life
- The jig is up and the game is up
- The jury is out
- The late
- The penny dropped
- The penny dropped
- The quick and the dead
- The real McCoy
- The road less traveled
- The road to hell is paved with good intentions
- The rub
- The seven deadly sins
- The seven-year itch
- The vs thee
- The whole megillah
- The world is one's oyster
- The worse for wear
- Theater vs. theatre
- Their, them, themselves, they (as singular pronouns)
- Their, there, they're
- Them's the breaks or brakes
- There's no free lunch
- Therefore
- Therefore vs therefor
- Thesauri or thesaurusus
- Think outside the box
- Third rail
- This ain't my first rodeo
- Tho, altho
- Thong or flip-flop
- Thoroughbred vs purebred
- Thrall
- Three sheets to the wind
- Three-ring circus
- Threshold or threshhold
- Threw vs. through
- Throes vs throws
- Throne vs thrown
- Through and through or thru and thru
- Through vs. thru
- Throw in the towel
- Throw shade
- Throw the baby out with the bathwater
- Throw under the bus
- Thrust, thrusted
- Thumb one’s nose and cock a snook
- Thumbs up and thumbs down
- Thusly
- Thyme vs time
- Tic vs. tick
- Tidbit vs. titbit
- Tiddlywinks and tiddleywinks
- Tide over
- Tide someone over vs tied someone over
- Tide vs tied
- Tie the knot
- Till, until, 'til
- Tilting at windmills
- Timber or timbre
- Timeout vs. time out
- Timpanum, timpani, tympanum, tympani
- Tinder vs tender
- Tinker's damn and tinker's dam
- Tinsel vs tensile
- Tinseltown
- Tiny house and tiny home
- Tire vs. tyre
- Tit for tat
- Titan vs tighten
- Title capitalization
- Titular
- Tmesis
- TMI
- To a T
- To boot
- To harp on
- To say the least and to say the least of it
- To the nines
- To vs. too
- To wit
- Toe the line
- Toe vs tow
- Toffee-nosed
- Toile vs toil
- Toile vs tulle
- Toilette
- Tole vs toll
- Tolerance vs. toleration
- Tomfoolery
- Tommy John surgery
- Ton vs. tonne
- Tongue-in-cheek
- Tontine
- Too big for one's britches or breeches and too big for one's boots
- Tool vs tulle
- Toot sweet
- Top banana and second banana
- Top dog
- Topography vs. typography
- Tor vs tore
- Torrent vs torrid
- Torturous vs. tortuous
- Toss-up
- Totaled/totaling vs. totalled/totalling
- Touch and go
- Touch base
- Touche or touché
- Tough row to hoe
- Tough vs tuff
- Tour de force
- Tout
- Toward vs. towards
- Toweled or towelled
- Towhead
- Toxicology vs. toxology
- Track and field and athletics
- Track vs tract
- Tractable vs trackable
- Tragedy vs travesty
- Trainer or trainor
- Training wheels vs stabilisers
- Traitor vs trader
- Transgender, transsexual, transvestite
- Translucent vs. transparent
- Transparent, translucent and opaque
- Transpire
- Transport vs. transportation
- Trap vs entrap
- Traveled/traveling vs. travelled/travelling
- Trawl vs. troll
- Treacle
- Treasurys
- Treatise vs treaties
- Treble vs. triple
- Trepidation
- Triage
- Trial by fire
- Trick or treat vs trick-or-treat
- Trip the light fantastic
- Trochee
- Troglodyte
- Troika
- Trolling
- Troop vs. troupe
- Trooper or trouper
- Trope
- Truck with
- Truculent
- Trussed vs trust
- Trustee vs. trusty
- Tsk-tsk
- Tsunami vs tidal wave
- Tumor vs. tumour
- Tunneled, tunneling vs. tunnelled, tunnelling
- Turban vs turbine
- Turbid, turgid, torpid
- Turducken
- Turn a blind eye
- Turn over a new leaf
- Turnabout is fair play
- Turnkey vs turn key
- Turnstile vs turnbuckle
- Turpitude vs turpentine
- Turtle, tortoise, terrapin
- Tussie-mussie vs nosegay
- Twee
- Tween
- Tween or teen
- Twelve days of Christmas
- Twiddle one's thumbs
- Two-bit
U
- U.S. state demonyms
- Uber
- Ubiquitous
- Udder vs. utter
- Ugly duckling
- Ulterior motive
- Umbrage
- Unawares
- Uncle Sam
- Uncomparable adjectives
- Under someone's thumb
- Under the auspices of
- Under the weather
- Underdog
- Underlie or underline
- Underwater vs. under water
- Underway vs. under way
- Undo vs undue
- Undoubtably vs. undoubtedly
- Unexceptionable vs unexceptional
- Unfamous or infamous
- Union Jack
- Unique
- United States (plural or singular?)
- Unkempt, unkept
- Unknown quantity
- Unpack
- Unputdownable
- Unsung hero
- Until one is blue in the face
- Untoward
- Unwitting vs unwilling
- Up and at ‘em vs up and Adam or atom
- Up one's sleeve and an ace up one's sleeve
- Up the creek and up a creek
- Up to date
- Up to snuff
- Up to speed
- Upfront vs. up front
- Upload vs download
- Upmost vs. utmost
- Upper crust
- Upper hand
- Upshot
- Urban legend and urban myth
- Urban vs urbane
- Urban, suburban and rural
- Used to
- Usually always
V
- Vacuous vs. vapid
- Vagabond and vagrant
- Vagina vs. vulva
- Vain, vein, and vane
- Vale, vail, or veil
- Valedictorian and salutatorian
- Valentine's Day
- Vamoose
- Vanguard
- Variance vs variants
- Varied vs various
- Variety is the spice of life
- Variety vs varietal
- Vary vs very
- Vaudeville
- Vegetarian vs vegan
- Venal vs venial
- Veracity vs. voracity
- Verb Viper
- Verbatim vs paraphrase
- Verbiage
- Verbs
- Verklempt
- Vernacular
- Verses vs. versus
- Vertex vs. vortex
- Vertigo vs vertiginous
- Very
- Vested
- Veteran vs veterinarian
- Vice president (capitalization and hyphenation)
- Vice versa
- Vice vs. vise
- Vicious vs. viscous
- Vicissitude
- Victory lap and honour lap
- Vigilant vs vigilante
- Vigor, vigour and vigorous
- Vim and vigor
- Violation vs volition
- Viral vs virile
- Virgule
- Virtual reality
- Vis-a-vis
- Visor vs vizier
- Vitiate
- Vitriol vs vitreous
- Vittle vs vital
- Viz.
- Voicemail
- Voilà
- Voluptuous vs voluminous
- Vouchsafe
- Vox populi
W
- W00t
- Wack vs. whack
- Waddle vs. wattle
- Wagon vs. waggon
- Wainscot or chair rail
- Waist vs. waste
- Wait vs weight
- Waive vs. wave
- Waiver vs. waver
- Wake vs awake
- Walk a mile in someone else's shoes
- Wallflower
- Wallop and pack a wallop
- Wander vs. wonder
- Wane, wax
- Wangle vs wrangle
- Wanton vs. wonton
- Ware, wear and where
- Warm the cockles of one's heart
- Warn vs worn
- Warrantee vs. warranty
- Wart vs wort
- Warts and all
- Wary vs. weary
- Was vs were
- Wash one’s hands of
- Wassail
- Watch the birdie
- Water under the bridge
- Waterloo or meet one's waterloo
- Watershed moment
- Watt vs what
- We'd vs weed
- Weak vs week
- Weakest link
- Wean vs ween
- Wear the trousers and wear the pants
- Weather vs whether
- Weaved, wove, woven
- Web site vs. website
- Website vs. web page
- Weekend
- Well-being vs. wellbeing
- Well-heeled
- Welsh
- Wench vs winch
- Wend vs wind
- Were vs we're
- Wet behind the ears
- Wet one’s whistle
- Wet vs. whet
- Whac-A-Mole
- Whacks vs wax
- Whale, wail or wale
- Whatnot
- Wheel and deal
- Wheelhouse
- When all is said and done
- When push comes to shove
- When the cat's away the mice will play
- Whence vs. from whence
- Where there's a will there's a way
- Whereas
- Wherewithal
- Whet one's appetite vs wet one's appetite
- Which vs witch
- Whig vs wig
- While away vs. wile away
- While vs wile
- Whilst
- Whine vs wine
- Whinge
- Whiny, whiney, whinny, Whinney
- Whippersnapper
- Whipping boy
- Whipsaw
- Whir or whirr vs were
- Whirl vs whorl
- Whirling dervish
- Whiskey vs. whisky
- White Christmas
- White elephant
- White lie
- Whitewash
- Whiz, whizz, wiz
- Who vs. whom
- Who's vs. whose
- Who's Who
- Whoa vs woe
- Whoever vs. whomever
- Whole ball of wax
- Whole kit and caboodle
- Whole nine yards
- Whole shebang
- Wholistic and holistic
- Whoop vs. whup
- Widow's peak
- Widow, widower
- Wiki
- Wild goose chase
- Wilful vs. willful
- Will-o'-the-wisp
- Willy-nilly
- Win-win or lose-lose
- Wing it
- Winningest
- Wintery vs wintry
- Wiseacre
- Wit vs. whit
- Witching hour
- With all due respect
- With egg on one's face
- Wither vs. whither
- Without further ado vs without further adieu
- Wobble vs warble
- Womp womp
- Won vs one
- Wonder vs. wonderment
- Wonkish, wonky
- Wont
- Wont vs won't
- Wood vs would
- Woodward English
- Woolen vs. woollen
- Woolgathering
- Word of mouth
- Word Sort
- Word to the wise
- WordFall
- Work in progress vs work in process
- Workout vs. work out
- World vs whirled
- Worrywart and worryguts
- Worse comes to worst
- Worst vs wurst
- Worth one's salt
- Worth one's while
- Would have, would've or would of
- Would just as soon or assume
- Wrath vs rath
- Wreak havoc (and wreaked vs. wrought)
- Wreak vs wreck
- Wreath vs. wreathe
- Wreck vs reck
- Wrench and spanner
- Writ large
- Write-off vs. write off
- Writer's block
- Writing at Its Best
- Writing World.com
- Wrong vs. wrongly
- Wrote vs rote
- Wunderkind
- WWJD
X
- X marks the spot
- Xmas
Y
- Y'all
- Y'all vs yawl
- Yada yada
- Yam vs sweet potato
- Yarn-bomb
- Yea, yeah, yay
- Yester
- Yiddish
- Yoghurt vs. yogurt
- Yoke vs. yolk
- YOLO
- Yore vs your or you’re
- You (in formal writing)
- You reap what you sow
- Young Turk
- Your vs. you're
- Youth or youths
- Youthquake
- Yule vs you'll
- Yuletide
Z
- Zee vs. zed
- Zeitgeist
- Zero tolerance
- Zero-sum game
- Zigzag