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insane

American  
[in-seyn] / ɪnˈseɪn /

adjective

  1. (not in technical use as a medical diagnosis) not sane; not of sound mind; mentally deranged.

    Synonyms:
    irrational, foolish, maniacal, crazy, crazed, lunatic, demented
  2. of, relating to, or characteristic of a person who is mentally deranged.

    a wild and insane look on her face.

  3. Law. considered to be or to have been affected with insanity, and therefore lacking legal responsibility or legal capacity.

    The judge deemed him criminally insane on the basis of his delusions and hallucinations.

  4. temporarily unable to think clearly.

    I think I'm going insane from all the noise outside.

  5. utterly senseless.

    an insane plan.

  6. Slang. excessive or extravagant; extreme.

    This much snow in April is just insane!

  7. Slang. astonishingly great; wonderful.

    Without his insane performance, the film would've been a total flop.


insane British  
/ ɪnˈseɪn /

adjective

    1. mentally deranged; crazy; of unsound mind

    2. ( as collective noun; preceded by the )

      the insane

  1. characteristic of a person of unsound mind

    an insane stare

  2. irresponsible; very foolish; stupid

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Related Words

See mad.

Other Word Forms

  • insanely adverb
  • insaneness noun
  • pseudoinsane adjective

Etymology

Origin of insane

First recorded in 1550–60; from Latin insānus “unsound (of mind), demented, frenzied”; in- 3, sane

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.

“The reaction has been more insane than I’ve ever seen for any of the shows we ever did with Brian,” he says.

From Los Angeles Times

But the effervescent co-host of the hit “Girls Gotta Eat” podcast will do more than just tell her “crazy, insane stories for an hour.”

From Los Angeles Times

"The stories and experiences Neil has been able to share with us are insane."

From BBC

A supporter of my insane ideas and concepts.

From Los Angeles Times

Despite his comedy specials having massive views, an insane tour schedule that includes his first arena, and plans to release three specials this year, he stays remarkably grounded.

From Los Angeles Times