lunacy vs folly

lunacy and folly both are nouns.

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

As nouns, lunacy and folly are synonyms defined as:

Other synonyms of lunacy include craziness, foolery, indulgence, tomfoolery.

lunacy (noun)	folly (noun)
foolish or senseless behavior	foolish or senseless behavior
obsolete terms for legal insanity	a stupid mistake
	the trait of acting stupidly or rashly
	the quality of being rash and foolish