Lunacy
/ˈluː.nə.si/noun
A state of severe mental illness or wildly irrational behavior.
Did you know?In medieval and early modern Europe, lunar influence was taken seriously enough that legal and medical writers tied periods of madness to the Moon’s cycles, helping turn astrology into language.
Etymological Timeline
Proto-Indo-European
PIE
*mḗh₁n̥s
“moon; month”
Latin
Latin
lūna
“the Moon”
Late Latin
Latin
lūnāticus
“moonstruck; mentally deranged”
Old French
Old French
lunatique
“moonstruck; insane”
Middle English
English
lunatic
“a person affected by the Moon; insane”
16th Century
English
lunacy
“madness; insanity”