LUNACY
folly, foolery, tomfoolery, craziness, lunacy, indulgence
(noun) foolish or senseless behavior
lunacy, madness, insaneness
(noun) obsolete terms for legal insanity
Source: WordNet® 3.1
Etymology
Noun
lunacy (countable and uncountable, plural lunacies)
(of a person or group of people) The state of being mad, insanity
a cyclical mental disease, apparently linked to the lunar phases
insanity implying legal irresponsibility.
Something deeply misguided.
Synonyms
• (state of being mad): insanity, madness, craziness, craze
Source: Wiktionary
Lu"na*cy, n.; pl. Lunacies. Etym: [See Lunatic.]
1. Insanity or madness; properly, the kind of insanity which is
broken by intervals of reason, -- formerly supposed to be influenced
by the changes of the moon; any form of unsoundness of mind, except
idiocy; mental derangement or alienation. Brande. Burrill.
Your kindred shuns your house As beaten hence by your strange lunacy.
Shak.
2. A morbid suspension of good sense or judgment, as through
fanaticism. Dr. H. More.
Syn.
– Derangement; craziness; mania. See Insanity.
Source: Webster’s Unabridged Dictionary 1913 Edition