Lunacy

Webster's Dictionary of the English Language

·noun A morbid suspension of good sense or judgment, as through fanaticism.

II. Lunacy ·noun 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.