Mum’s the Word – Idiom, Origin & Meaning

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Candace Osmond

Candace Osmond studied Advanced Writing & Editing Essentials at MHC. She’s been an International and USA TODAY Bestselling Author for over a decade. And she’s worked as an Editor for several mid-sized publications. Candace has a keen eye for content editing and a high degree of expertise in Fiction.

There’s a plethora of idiomatic expressions to choose from that can add character to your conversations and writing. One is “mum’s the word,” a phrase used to emphasize secrecy or the importance of keeping quiet about a particular matter. But there are some guidelines around using it, so let’s take a look.

Mum’s the Word Meaning

Sweet Tooth Idiom Meaning Origin

“Mum’s the word” is an idiomatic phrase that means to keep a secret or to stay silent about a certain matter. In English, we use it to show the importance of not revealing certain information or discussing a particular topic. In other words, “I have a secret, but you can’t tell anyone.”

Origin of the Phrase Mum’s the Word

It has nothing to do with a “mum” or “mom” or Egyptian mummies. It actually comes from a sound, the one you make when your mouth is closed, and you hum.

In print, it goes back to the 1300s in the Middle English poem by William Langland, titled “The vision of William Concerning Piers Plowman,” and read, “Thou mightest beter meten the myst on Malverne hulles. Then geten a mom of heore mouth til moneye weore schewed!”

In the 15th century, William Shakespeare’s play “Henry VI, Part 2” uses the term when a character says, “Seal up your lips, and give no words but mum.”

Personally, I always think about my childhood growing up in Newfoundland, Canada. During the Christmas holidays, we’d dress up in silly costumes and cover our faces with pillowcases or fabric masks and go door to door (of friends and family) to sing songs and share a drink. While there, the homeowners have to guess who you are, but you can’t say anything, and they’re called mummers because of it, and the English tradition itself was called mummering.

Mum Is the Word vs. Mum’s the Word

Mums the Word vs Mum is the Word Ngram
Mum’s the word and mum is the word usage trend.

You might find some people who use “mum is the word” and “mum’s the word” interchangeably, but the actual phrase to say it is “mum’s the word.” It’s also the more common version. Sure, both expressions convey the same meaning of staying quiet or keeping a secret, but “mum’s the word” is the original and more widely accepted version.

Mum’s the Word Synonyms

  • Keep it under wraps
  • Keep it hush-hush
  • On the QT
  • Maintain silence
  • On the down-lo 
  • Keep shtum
  • Shush your tush

Using Mum’s the Word in a Sentence

Mums the Word Idiom Origin Meaning
  • After learning about the surprise party for my cousin, I told her friend, “Mum’s the word, don’t let the birthday girl find out!”
  • We’ve been working so hard on this secret project, and our manager told the team, “This new project is confidential, so mum’s the word until we officially announce it.”
  • When Amy discovered her brother’s dark secret, she assured him, “Don’t worry, mum’s the word. I won’t tell anyone.”
  • We both agreed that mum’s the word regarding our awesome plans to start a new business together.
  • When the journalist received an anonymous tip, his source nervously insisted, “Mum’s the word! Don’t tell anyone where you got the information.”

Keep Quiet

Now, do you have a better understanding of how to use the phrase “mum’s the word”? I hope my tips and examples have given you all the info you need. Play around with it, and work it into your conversations and even your writing to add some color.

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