insane

[in-seyn]

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

/ ɪnˈseɪn /

adjective

1. 1. mentally deranged; crazy; of unsound mind

   2. ( as collective noun; preceded by the )

      the insane

2. characteristic of a person of unsound mind

   an insane stare

3. irresponsible; very foolish; stupid

Other Word Forms

• insanely adverb
• insaneness noun
• pseudoinsane adjective

Word History and Origins

Origin of insane¹

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

Synonym Study

See mad.

Example Sentences

“It was kind of like, ‘Yes, this is a little insane,’” said Kosinski, “‘but if we can pull it off, we’ll get something totally unique.’”

Read more on Los Angeles Times

Epstein called the president “borderline insane” the following month.

Read more on The Wall Street Journal

“The chaos that I saw going on over there was insane,” said the neighbor.

Read more on Los Angeles Times

“I’m not even convinced he’s telling us the truth. He could be completely insane.”

Read more on Literature

“I thought I was going insane,” one woman posted on a Topanga Facebook group after catching sight of the hairy quartet in this bohemian enclave of actors, musicians and other artsy types.

Read more on The Wall Street Journal

Related Words

• crazy 
• delirious 
• demented 
• deranged 
• frantic 
• frenzied 
• kooky 
• nutty