Main Entry:

lu·na·cy

Pronunciation:

\ˈlü-nə-sē\

Function:

noun

Inflected Form(s):

plural lu·na·cies

Etymology:

lunatic

Date:

1541

1 a: insanity b: intermittent insanity once believed to be related to phases of the moon2: wild foolishness : extravagant folly3: a foolish act