Four-letter words

[fawr-let-er, fohr-] /ˈfɔrˌlɛt ər, ˈfoʊr-/

noun
1.
any of a number of short words, usually of four letters, considered offensive or vulgar because of their reference to excrement or sex.
2.
any word, typically of four letters, that represents something forbidden, disliked, or regarded with extreme distaste:
In the dieter’s vocabulary, “cake” is a four-letter word.
noun
1.
any of several short English words referring to sex or excrement: often used as swearwords and regarded generally as offensive or obscene

Euphemism for the most common verbal obscenities.

Obscene (see obscenity) or very vulgar words of four letters, such as piss. Most four-letter words refer to excretion or sex.

noun phrase

Any of several short English words generally regarded as obscene or offensive (1920s+)
Any of several short English words that are generally regarded as vulgar or obscene. For example, No four-letter words are permitted in this classroom. This expression is applied mostly to words describing excretory or sexual functions. [ First half of 1900s ]