lu·​na·​tic | \ ˈlü-nə-ˌtik How to pronounce lunatic (audio) \

Definition of lunatic

1 dated
a : affected with a severely disordered state of mind : insane
b : designed for the care of mentally ill people a lunatic asylum
2 : wildly foolish a lunatic idea lunatic behavior

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Other Words from lunatic

lunatic noun

Synonyms & Antonyms for lunatic



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Examples of lunatic in a Sentence

He hatched a lunatic plot to overthrow the government. another of his lunatic ideas
Recent Examples on the Web But the weirdest, and most compelling, segment is one in which conspiracy theorist Jacob Wohl teams with Jack Burkman, a lobbyist and fellow traveler in the conservative conspiracy world, in a lunatic scheme. Arizona Republic, "HBO's 'After Truth' takes on fake news, and mostly wins. Here's why that may not be enough," 19 Mar. 2020 This is not some sort of lunatic conspiracy theory viewpoint of the American electorate. Nr Staff, National Review, "The ’90s Flashback Episode," 17 Jan. 2020 Sanders promises the most stubborn confrontation with this lunatic militarism on offer, and the best possibility that America might become a responsible member of the international community. Ryan Cooper, TheWeek, "Bernie Sanders is America's best hope for a sane foreign policy," 7 Jan. 2020 Though who could be jealous of a boy with no brothers and a lunatic dad? Tiphanie Yanique, The New Yorker, "God’s Caravan," 28 Oct. 2019 The first avalanche, the last leg at Lhakpa-Ri (three times) and a lunatic nighttime storm featuring a rogue boulder stand out as highlights despite Henry Lai’s on-the-nose score and some wonky CGI. Elizabeth Kerr, The Hollywood Reporter, "'The Climbers' ('Pan deng zhe'): Film Review," 1 Oct. 2019 Someone who might take our hand, as if taking the hand of an errant toddler, and gently guide us away from the lunatic precipice that the ‘logic’ of profit unguided by the compass of feeling has brought us to. Sydney Bucksbaum,, "Brit Marling responds to The OA cancelation fan hunger strike: 'No one is coming to the rescue'," 24 Aug. 2019 The El Paso massacre, carried out by a white nationalist waging a lunatic war against Hispanic immigration, is being used as a bludgeon against Trump, and immigration restriction more broadly. Rich Lowry, National Review, "Immigration Restriction Is Not Hate," 9 Aug. 2019 The physical comedy requires the cast members to boomerang around the set with lunatic abandon. Charles Mcnulty,, "Review: How funny is ‘The Play That Goes Wrong’? Depends on your appetite for pranks and pratfalls," 12 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lunatic.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of lunatic

14th century, in the meaning defined at sense 1a

History and Etymology for lunatic

Middle English lunatik, from Anglo-French or Late Latin; Anglo-French lunatic, from Late Latin lunaticus, from Latin luna; from the belief that lunacy fluctuated with the phases of the moon

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Time Traveler for lunatic

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The first known use of lunatic was in the 14th century

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Cite this Entry

“Lunatic.” Dictionary, Merriam-Webster, Accessed 11 Jul. 2020.

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How to pronounce lunatic (audio)

English Language Learners Definition of lunatic

old-fashioned + sometimes offensive : designed for insane people
: not sane
: wildly foolish


lu·​na·​tic | \ ˈlü-nə-ˌtik How to pronounce lunatic (audio) \

Kids Definition of lunatic

 (Entry 1 of 2)



Kids Definition of lunatic (Entry 2 of 2)

1 : an insane person
2 : a person who behaves very foolishly That lunatic went through a red light.


lu·​na·​tic | \ ˈlü-nə-ˌtik How to pronounce lunatic (audio) \

Medical Definition of lunatic

dated, now offensive : an individual marked by a severely disordered state of mind

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lu·​na·​tic | \ ˈlü-nə-tik \

Legal Definition of lunatic

: an insane person used especially formerly

Other Words from lunatic

lunatic adjective

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More from Merriam-Webster on lunatic

Thesaurus: All synonyms and antonyms for lunatic

Rhyming Dictionary: Words that rhyme with lunatic

Spanish Central: Translation of lunatic

Nglish: Translation of lunatic for Spanish Speakers

Britannica English: Translation of lunatic for Arabic Speakers

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