insanity

in·san·i·ty | \ in-ˈsa-nə-tē

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

Synonyms & Antonyms On the Meaning of Insanity More Example Sentences Learn More about insanity

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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

Recent Examples on the Web Oberhansley rejected his defense team's insanity case last June and the a trial began in August. — Lucas Aulbach, The Courier-Journal, "6+ years later, Joseph Oberhansley found guilty of murder in Indiana cannibalism case," 19 Sep. 2020 Some patients are criminal defendants, including those awaiting competence hearings and found not guilty by reason of insanity. — Washington Post, "St. Elizabeths has increased usage of restraints on patients, report says," 15 Sep. 2020 My message was not an emotional plea for help but an angry political statement about the rampant insanity leading us off a cliff. — The Washington Post, "Color of Money," 10 Sep. 2020 Ultimately, both Geyser and Weier entered insanity pleas. — Christopher Kuhagen, Milwaukee Journal Sentinel, "One of two girls in the Waukesha Slender Man stabbing case loses an appeal; court says adult court was the right venue," 13 Aug. 2020 This was insanity, because 5 million Americans became first-time gun owners in the first half of 2020. — Michael Brendan Dougherty, National Review, "How They Lost," 4 Sep. 2020 No one alive today is going to live long enough to see the end of this insanity. — Nick Canepa Columnist, San Diego Union-Tribune, "Column: Efforts of NBA are noble, but what will it change?," 29 Aug. 2020 That's certainly the case for the insanity of Pump It Up! — Sam Machkovech, Ars Technica, "The best game-breaking speedruns of Summer Games Done Quick 2020," 24 Aug. 2020 There is so much about this series that people will relate to but your characters’ story especially feels so universal for anyone in their 20s and 30s who has been single during all of this insanity. — Sydney Bucksbaum, EW.com, "Listen to the emotional original ballad from Love in the Time of Corona," 20 Aug. 2020

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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Last Updated

3 Oct 2020

Cite this Entry

“Insanity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/insanity. Accessed 26 Oct. 2020.

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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

See the full definition for insanity in the English Language Learners Dictionary

insanity

noun

in·san·i·ty | \ in-ˈsa-nə-tē

Kids Definition of insanity

: the condition of being abnormal or unhealthy in mind

insanity

noun

in·san·i·ty | \ in-ˈsan-ət-ē

plural insanities

Medical Definition of insanity

1 dated : a severely disordered state of the mind usually occurring as a specific disorder

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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