mishegaas vs lunacy

mishegaas and lunacy both are nouns.

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

As nouns, lunacy is a hypernym of mishegaas; that is, lunacy is a word with a broader meaning than mishegaas:

Other hypernyms of mishegaas include craziness, folly, foolery, indulgence, tomfoolery.

mishegaas (noun)	lunacy (noun)
(Yiddish) craziness; senseless behavior or activity	foolish or senseless behavior
	obsolete terms for legal insanity