folly vs mishegaas

folly and mishegaas both are nouns.

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

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

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

folly (noun)	mishegaas (noun)
foolish or senseless behavior	(Yiddish) craziness; senseless behavior or activity
a stupid mistake
the trait of acting stupidly or rashly
the quality of being rash and foolish