Skip to content
ARCHIEENGLISH
LearnPlayWordsRanking
  • Learn
  • Play
  • Words
  • Ranking
  • Mine
← Vocabulary

lunacy

UK/ˈluː.nə.si/US/ˈluː.nə.si/
nounC2Very rare — outside the 30,000 commonest English words, so you will meet it in writing rather than in speechneutral

Lunacy is behaviour so wild it looks like madness. Used almost entirely about decisions rather than about people.

That is the modern use, and calling a policy sheer lunacy is a criticism of the thinking rather than a diagnosis. The older sense was literal and legal, since a lunatic was a formal category into the twentieth century, and both words come from the moon, from the belief that madness followed its phases. Applied to a person today either word is unkind and inaccurate.

Definitions of lunacy

  1. 1nounlunacyExtremely foolish or reckless behaviour.C2

    “Selling the building was economic lunacy.”

Also accepted in games: madness, insanity

Where it comes from

From lunatic + -acy.

Etymology from Wiktionary, CC BY-SA

Practised in A Man Called Ove

First appears in chapter 4 of A Man Called Ove.

Practise this word

lunacy in the wild

  • A social reformer who was called the "Poor Man's Earl", he campaigned for better working conditions, reform to lunacy laws, education and the limitation of child labour.

    Anthony Ashley-Cooper, 7th Earl of Shaftesbury

  • By the late 1980s, there were at least 40 published studies on the purported lunar-lunacy connection, and at least 20 published studies on the purported lunar-birthrate connection.

    Lunar effect

From Wikipedia, CC BY-SA 4.0. These sentences were written by other people about their own subjects; they are here to show the word at work, not as anybody’s opinion.