dirty joke vs joke

dirty joke and joke both are nouns.

Word	Noun	Adjective	Verb	Adverb
dirty joke	Yes	No	No	No
joke	Yes	No	Yes	No

As nouns, joke is a hypernym of dirty joke; that is, joke is a word with a broader meaning than dirty joke:

Other hypernyms of dirty joke include gag, jape, jest, laugh.

dirty joke (noun)	joke (noun)
an indelicate joke	a ludicrous or grotesque act done for fun and amusement
	activity characterized by good humor
	a triviality not to be taken seriously
	a humorous anecdote or remark intended to provoke laughter

dirty joke (verb)	joke (verb)
	act in a funny or teasing way
	tell a joke; speak humorously