Four-letter word is an idiom that came into use in the twentieth century. We will examine the meaning of the idiomatic phrase four-letter word, where it came from, and some examples of its use in sentences.
The expression four-letter word is a euphemism for an offensive word not usually used in polite company that is a sexual term, a swear word, or a scatological term. Though most of the offensive words that are considered four-letter words do actually consist of four letters, not all terms that are considered four-letter words actually consist of four letters. Any person, thing or institution may be idiomatically branded a four-letter word if it has become a disgrace or an embarrassment. At one time, four-letter words were only exchanged among the closest of male friends and were considered “locker room talk.” Now, the use of four-letter words is more accepted in casual conversation, but they are still considered forbidden in conversations with superiors or casual acquaintances. Four-letter words should never be used in business correspondence. While many consider the use of four-letter words acceptable, others consider their use crass and offensive. The idiom four-letter word came into use in the 1920s, a time when many slang terms and idioms were coined. The plural of four-letter word is four-letter words, and the term should be spelled with the hyphen.
Same will be true with the Iowa caucus, which became a four-letter word last week. (The Charleston Gazette-Mail)
As the story goes, Brooks stormed into the locker room during the second intermission, paced back and forth, pointed his finger, and used a certain four-letter word to remind his players that if they lost that game, they would take it to their graves. (The Bemidji Pioneer)
He created unflattering nicknames for his opponents, frequently treated compromise as a four-letter word, and viewed politics as a war for power. (The Canton Repository)
Unless you’re a sailor, using four-letter words in the workplace is generally frowned upon. (The Tennessean)