Definition of f-word:
(n) :
(euphemistic) The word fuck (or inflected forms like fucking) or fucker.
(n) :
(euphemistic) The word fag or faggot.
(v) :
(euphemistic) To use vulgarities, especially the word fuck.
(n) :
Any word beginning with f that is not normally taboo but is considered (often humorously) to be so in the given context.
(n) :
Alternative letter-case form of f-word. [(euphemistic) The word fuck (or inflected forms like fucking) or fucker.]