in-joke vs laugh

in-joke and laugh both are nouns.

Word	Noun	Adjective	Verb	Adverb
in-joke	Yes	No	No	No
laugh	Yes	No	Yes	No

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

in-joke: a joke that is appreciated only by members of some particular group of people
laugh: a humorous anecdote or remark intended to provoke laughter

Other hypernyms of in-joke include gag, jape, jest, joke.

in-joke (noun)	laugh (noun)
a joke that is appreciated only by members of some particular group of people	the sound of laughing
	a humorous anecdote or remark intended to provoke laughter
	a facial expression characteristic of a person laughing

in-joke (verb)	laugh (verb)
	produce laughter