insanity
Americannoun
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(not in technical use as a medical diagnosis) the condition of being insane; a derangement of the mind.
- Synonyms:
- madness, lunacy, aberration, mania, craziness
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Law. such unsoundness of mind as frees one from legal responsibility, as for committing a crime, or as signals one's lack of legal capacity, as for entering into a contractual agreement.
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Psychiatry. (formerly) psychosis.
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extreme foolishness.
Trying to drive through that traffic would be pure insanity.
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a foolish or senseless action, policy, statement, etc..
We've heard decades of insanities in our political discourse.
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noun
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relatively permanent disorder of the mind; state or condition of being insane
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law a defect of reason as a result of mental illness, such that a defendant does not know what he or she is doing or that it is wrong
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utter folly; stupidity
Other Word Forms
Noun Inflected Forms
Etymology
Origin of insanity
First recorded in 1580–90; from Latin insānitāt-, stem of insānitās “unsoundness of mind, insanity”; see origin at in- 3, sanity
Explanation
Insanity is an ongoing state of extreme mental illness, which may cause abnormal or antisocial behaviors. If you bark at cats and meow at dogs, you might suffer from insanity. The noun insanity originates from the Latin word insanitatem, meaning "unhealthfulness" relating to the mind. It is believed that master artist Vincent van Gogh, who cut off his ear and gave it to a prostitute, experienced periods of insanity. But this term can also refer to things people perceive as unconventional or foolish, like your neighbor who quit his job, sold all his belongings, and bought a boat to sail around the world.
Vocabulary lists containing insanity
Adrift
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salu, san (health)
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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.
Wilson started to struggle after eating his eighth chicken wing, which was coated in Da Bomb, Beyond Insanity hot sauce.
From Salon • Jun. 27, 2025
The lineup of sauces changes every season, but a mainstay is the brutal Da’ Bomb Beyond Insanity, a turning point in nearly every interview.
From New York Times • Apr. 3, 2023
He is the author of “The Devil Himself: A Tale of Honor, Insanity, and the Birth of Modern America” and co-author of “The Prophet of Harvard Law.”
From Washington Post • Dec. 26, 2022
Paul McNeil: Insanity is doing the same thing over and over and expecting different results.
From BBC • Feb. 26, 2022
It took him considerably less than an hour to reach the edge of the Cliffs of Insanity.
From "The Princess Bride" by William Goldman
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.
