lunatic
Americannoun
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lunatics
plural
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(no longer in technical use; now considered offensive) an insane person.
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a person whose actions and manner are marked by extreme eccentricity or recklessness.
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a person legally declared to be of unsound mind and who therefore is not held capable or responsible before the law: a former legal term.
adjective
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(no longer in technical use; now considered offensive) insane.
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characteristic or suggestive of lunacy; wildly or recklessly foolish.
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Older Use. designated for or used by the insane.
a lunatic asylum.
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gaily or lightheartedly mad, frivolous, eccentric, etc..
She has a lunatic charm that is quite engaging.
adjective
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an archaic word for insane
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foolish; eccentric; crazy
noun
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of lunatic
1250–1300; Middle English lunatik, from Old French lunatique, from Late Latin lūnāticus “moonstruck.” See Luna, -tic ( def. )
Explanation
A lunatic is someone who is either clinically insane or just acting really crazy. Someone driving too fast and zigging in and out of traffic is driving like a lunatic. The root of this word is luna, which means moon. That's because lunatic originally meant someone who went crazy with every phase of the moon, kind of like a werewolf. Most people these days don't believe in moon-caused insanity, but we still talk about lunatics, sometimes meaning clinically insane people. More often this is a slang term, used mainly in exaggerations, for anyone who seems wild and out of control.
Vocabulary lists containing lunatic
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Harry Potter and the Prisoner of Azkaban
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Twelfth Night
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Ireland's police chief at the time, Drew Harris blamed the rioting on a "lunatic, hooligan faction driven by a far-right ideology".
From BBC ● Jul. 1, 2026
"The city is going to bear the scars of this lunatic for a really long time."
From Barron's ● May 15, 2026
He looked at me like I was a lunatic, but he heard me, so perhaps I planted a seed.
From The Wall Street Journal ● Mar. 29, 2026
Mr. Gittlitz writes with the lunatic panache of a utopian manifesto or 2000s sports blog.
From The Wall Street Journal ● Mar. 27, 2026
At last he spluttered, “The Quibbler? That lunatic rag of Xeno Lovegood’s?”
From "Harry Potter and the Deathly Hallows" by J.K. Rowling
He is the one figure in the story who learns something: How to survive among lunatics.
From The Wall Street Journal ● Apr. 23, 2026
The “founders and VCs” here are the miners and early buyers who picked up bitcoin at $10, $100, $1,000 — and held on while the rest of us called them lunatics.
From MarketWatch ● Nov. 17, 2025
"It's not my fault that some lunatics use this as a stage to do things which I expressly do not support," he tells me.
From BBC ● May 8, 2024
What signs of sanity are out there to counter the lunatics?
From Salon ● Apr. 11, 2023
Maddy and Stephanie are screaming like lunatics, hands on their cheeks.
From "A Place at the Table" by Saadia Faruqi and Laura Shovan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
