craziness vs mishegaas

craziness and mishegaas both are nouns.

Word	Noun	Adjective	Verb	Adverb
craziness	Yes	No	No	No
mishegaas	Yes	No	No	No

As nouns, mishegaas is a hyponym of craziness; that is, mishegaas is a word with a more specific, narrower meaning than craziness:

Other hyponyms of craziness include meshugaas, mishegoss, buffoonery, clowning, frivolity, harlequinade, japery, prank.

craziness (noun)	mishegaas (noun)
foolish or senseless behavior	(Yiddish) craziness; senseless behavior or activity
the quality of being rash and foolish
informal terms for insanity