have a go at it vs dirty word

have a go at it is not a noun while dirty word is a noun.

Word	Noun	Adjective	Verb	Adverb
have a go at it	No	No	Yes	No
dirty word	Yes	No	No	No

have a go at it (noun)	dirty word (noun)
	an offensive or indecent word or phrase
	a word that is considered to be unmentionable

have a go at it (verb)	dirty word (verb)
have sexual intercourse with