lunacy

noun

lu·​na·​cy ˈlü-nə-sē 

plural lunacies

1

dated

a

: insanity sense 1

b

: intermittent insanity once believed to be related to phases of the moon

2

: wild foolishness : extravagant folly

3

: a foolish act

Synonyms

• absurdity
• asininity
• bêtise
• fatuity
• folly
• foolery
• foppery
• idiocy
• imbecility
• inanity
• insanity
• stupidity

Examples of lunacy in a Sentence

Quitting her job was lunacy.

His idea was considered total lunacy.

Recent Examples on the Web

Nothing was going right: nobody had jobs and there were strikes every day and food shortages and super-sensational murders and politicians accusing one another of all sorts of lunacies. —Junot Díaz, The New Yorker, 30 Oct. 2023

As a documentary subject, free diving has the death-defying lunacy of big-wave surfing and the cosmopolitan appeal of Formula 1. —Taylor Antrim, Vogue, 22 Sep. 2023

As a competitive sport, free diving has the death-defying lunacy of big-wave surfing and the cosmopolitan appeal of Formula One (gorgeous people, competitions in exotic locations). —Taylor Antrim, Vogue, 19 July 2023

The only thing missing from the Tundra's lineup is a direct competitor that answers the lunacy of the Ford F-150 Raptor and Ram 1500 TRX. —Austin Irwin, Car and Driver, 12 July 2023

Ratcheting up the Rolaids-gobbling reality of that assignment: Nevin manages two-way megastar Shohei Ohtani, the best player on earth with all the uncharted lunacy that comes with him, along with some guy named Mike Trout. —Bryce Miller, San Diego Union-Tribune, 4 July 2023

The situations the protagonists face are specific to Iran, but their escalating lunacy is universal. —David Rooney, The Hollywood Reporter, 28 May 2023

Within many of our most crucial institutions, suppositions that would have been considered the height of lunacy even a few years ago have become regnant overnight. —Charles C. W. Cooke, National Review, 27 June 2023

Played with typical, affable lunacy by Marino, Streeter is simultaneously omnipresent in the Dubeks’ lives and tempting to take for granted — precisely how the character views himself. —Kenny Herzog, Vulture, 2 June 2023

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Word History

Etymology

lunatic

First Known Use

1541, in the meaning defined at sense 1a

Kids Definition

lunacy

noun

lu·​na·​cy ˈlü-nə-sē 

plural lunacies

: insanity sense 1

—used chiefly in the past

Medical Definition

lunacy

noun

lu·​na·​cy ˈlü-nə-sē 

plural lunacies

dated

: mental illness

also : intermittent mental illness once believed to be related to phases of the moon

Legal Definition

lunacy

noun

lu·​na·​cy ˈlü-nə-sē 

: insanity