(euphemistic) The word fuck or faggot.Oh, f-word, I've lost the keys.The dialogue was littered with f-words.
Any word beginning with f that is not normally taboo but is considered (often humorously) to be so in the given context.She has no luck with diets. Don't mention the f-word (by which I mean "fat").
Verb
(euphemistic) To use vulgarities.
2010, Alan L. Greenberg, Confessions of a Government Man: How to Succeed in Any Bureaucracy, Her plain-Jane appearance lulled the Secret Service representatives for a while but it wasn't long before she out f-worded them and became the assertive one in this space chase, ...