wow vs joke

wow and joke both are nouns.

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

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

Other hypernyms of wow include gag, jape, jest, laugh.

wow (noun)	joke (noun)
a joke that seems extremely funny	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

wow (verb)	joke (verb)
impress greatly	act in a funny or teasing way
	tell a joke; speak humorously