lunacy Meaning, Definition & Usage

noun obsolete terms for legal insanity
madness; insaneness.
noun foolish or senseless behavior
indulgence; foolery; craziness; tomfoolery; folly.

See Lunatic.

plural Lunacies

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.
A morbid suspension of good sense or judgment, as through fanaticism. Dr. H. More. Syn. -- Derangement; craziness; mania. See Insanity.