insanity

noun
in·​san·​i·​ty | \ in-ˈsa-nə-tē How to pronounce insanity (audio) \
plural insanities

Definition of insanity

1 dated : a severely disordered state of the mind usually occurring as a specific disorder
2 law : unsoundness of mind or lack of the ability to understand that prevents one from having the mental capacity required by law to enter into a particular relationship, status, or transaction or that releases one from criminal or civil responsibility
3a : extreme folly or unreasonableness the insanity of violence His comments were pure insanity.
b : something utterly foolish or unreasonable the insanities of modern life

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Synonyms & Antonyms for insanity

Synonyms

aberration, dementia, derangement, lunacy, madness, mania, rage [archaic]

Antonyms

mind, saneness, sanity

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On the Meaning of Insanity

An oft-quoted bon mot (frequently attributed to Albert Einstein, Benjamin Franklin, or a number of other people who probably never said it) is that insanity may be defined as “doing the same thing over and over and expecting different results.” While the job of lexicographers might be easier if they were allowed to use witty sayings instead of precise definitions, such belletristic labors are not within their purview. The straight facts about insanity are these: it has been in use in English since the late 16th century, for the first two hundred years or so carrying only the literal meaning “the condition of being mentally deranged.” In the 19th century it began to take on a looser sense, “extreme folly or unreasonableness.” In modern usage, insanity may be found in both senses: you may tell your brother that trying to skateboard while holding onto a car is "insanity" (in which case you mean that it is extremely foolish) or encounter the stricter original meaning in such contexts as insanity plea.

Examples of insanity in a Sentence

She was found not guilty by reason of insanity. His friends thought his decision to quit his job was pure insanity. Please, no more violence. It's time to stop this insanity. the insanities of modern life
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Recent Examples on the Web

However, defense attorneys agreed to drop an insanity or mental health defense as part of the agreement, according to the News and Tribune. Ben Tobin, The Courier-Journal, "Death penalty taken off the table for accused cannibal from Southern Indiana," 2 July 2019 The red, white and blue donned by both U.S. and French fans blended into one cohesive sea of rising insanity as kickoff approached. Ashley Scoby, Pro Soccer USA, "U.S., France atmosphere lives up to hype in World Cup prize fight," 29 June 2019 In New York, a defendant must prove their inability to distinguish right from wrong in order to win an insanity plea defense. Sonia Moghe, CNN, "Princeton grad killed father over allowance, prosecutors say. His attorney says he's mentally ill," 27 June 2019 The prosecution recently asked to do its own psychological evaluation of Pagourtzis in anticipation of a possible insanity plea. Nick Powell, Houston Chronicle, "Accused Santa Fe school shooter to be tried in Richmond," 21 June 2019 There’s gotta be some sort of a reasonable judge that says this is insanity. Madison Roberts, PEOPLE.com, "Jeff Lewis Says He and Ex Gage Edward Hired Lawyers in 'Ugly' Custody Battle Over Daughter Monroe," 20 June 2019 But maybe her apparent insanity is the only sane reaction to Gilead. Elena Nicolaou, refinery29.com, "What's The Deal With Commander Lawrence's Wife In The Handmaid's Tale?," 20 June 2019 Anything else is insanity, stupidity, and the Pacers are not the Phoenix Suns. Gregg Doyel, Indianapolis Star, "Doyel: Goga Bitadze is a strange draft choice for the Pacers," 20 June 2019 Alvarez was there after being found not guilty for reasons of insanity in 2009 for battery on a police officer. Sukey Lewis, The Mercury News, "Excessive use of force by police chief’s son leads to arrest of patient at Napa State Hospital," 19 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'insanity.' 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 insanity

1590, in the meaning defined at sense 1

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Statistics for insanity

Last Updated

10 Jul 2019

Look-up Popularity

Time Traveler for insanity

The first known use of insanity was in 1590

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More Definitions for insanity

insanity

noun

English Language Learners Definition of insanity

: severe mental illness : the condition of being insane
: something that is very foolish or unreasonable

insanity

noun
in·​san·​i·​ty | \ in-ˈsa-nə-tē How to pronounce insanity (audio) \

Kids Definition of insanity

: the condition of being abnormal or unhealthy in mind

insanity

noun
in·​san·​i·​ty | \ in-ˈsan-ət-ē How to pronounce insanity (audio) \
plural insanities

Medical Definition of insanity

1 dated : a severely disordered state of the mind usually occurring as a specific disorder
2 law : unsoundness of mind or lack of the ability to understand that prevents one from having the mental capacity required by law to enter into a particular relationship, status, or transaction or that releases one from criminal or civil responsibility

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insanity

noun
in·​san·​i·​ty

Legal Definition of insanity

1 : unsoundness of mind or lack of the ability to understand that prevents one from having the mental capacity required by law to enter into a particular relationship, status, or transaction or that releases one from criminal or civil responsibility: as
a : a disease, defect, or condition of the mind that renders one unable to understand the nature of a criminal act or the fact that it is wrong or to conform one's conduct to the requirements of the law being violated
b : inability to understand and participate in legal proceedings brought against one : incompetence
c : inability to understand the nature and purpose of a punishment (as the death penalty) to which one has been sentenced
d : inability to understand the nature and consequences of one's acts (as making a will) or of events, matters, or proceedings in which one is involved — see also commitment, durham rule, irresistible impulse test, m'naghten test, not guilty by reason of insanity, substantial capacity test — compare capacity, competency, competent, diminished capacity, sanity
2 : the affirmative defense of having acted while insane

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Comments on insanity

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