fuck can be used as ANY part of speech... (ok... except as an article or preposition).
Noun: I don't give a fuck.
Verb, transitive: Larry fucks Suzi.
Verb, intransitive: Suzi fucks.
Adjective: I'm going to fucking Disneyland!
Adverb: Klawzie is fucking hot.
As almost every word in a proper sentence: Fucking fuck that fucking fucker.
Fuck is a comma.