fool vs joke

fool and joke both are nouns.

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

As verbs, joke is a hypernym of fool; that is, joke is a word with a broader meaning than fool:

Other hypernyms of fool include jest, play.

fool (noun)	joke (noun)
a person who lacks good judgment	a ludicrous or grotesque act done for fun and amusement
a person who is gullible and easy to take advantage of	activity characterized by good humor
a professional clown employed to entertain a king or nobleman in the Middle Ages	a triviality not to be taken seriously
	a humorous anecdote or remark intended to provoke laughter

fool (verb)	joke (verb)
indulge in horseplay	act in a funny or teasing way
fool or hoax	tell a joke; speak humorously
spend frivolously and unwisely
make a fool or dupe of