joke vs pun

joke and pun both are nouns.

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

As verbs, pun is a hyponym of joke; that is, pun is a word with a more specific, narrower meaning than joke:

Other hyponyms of joke include gag, quip, arse around, fool, fool around, horse around.

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

joke (verb)	pun (verb)
act in a funny or teasing way	make a play on words
tell a joke; speak humorously