[ in-seyn ]
/ ɪnˈseɪn /


not sane; not of sound mind; mentally deranged.
of, relating to, or characteristic of a person who is mentally deranged: insane actions; an insane asylum.
utterly senseless: an insane plan.

Nearby words

  1. ins,
  2. ins and outs,
  3. ins.,
  4. insalivate,
  5. insalubrious,
  6. insanely,
  7. insanitary,
  8. insanitation,
  9. insanity,
  10. insatiability

Origin of insane

From the Latin word insānus, dating back to 1550–60. See in-3, sane

Related formsin·sane·ly, adverbin·sane·ness, nounpseu·do·in·sane, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for insanely

British Dictionary definitions for insanely


/ (ɪnˈseɪn) /


  1. mentally deranged; crazy; of unsound mind
  2. (as collective noun; preceded by the)the insane
characteristic of a person of unsound mindan insane stare
irresponsible; very foolish; stupid
Derived Formsinsanely, adverbinsaneness, noun

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

Word Origin and History for insanely



1550s, from Latin insanus "mad, insane; outrageous, excessive, extravagant," from in- "not" (see in- (1)) + sanus "well, healthy, sane" (see sane). Originally only of persons; of actions, from 1842. Cf. lunatic; and Italian pazzo "insane," originally a euphemism, from Latin patiens "suffering." German verrückt, literally past participle of verrücken "to displace," "applied to the brain as to a clock that is 'out of order' " [Buck]. The noun meaning "insane person" is attested from 1786.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for insanely


[ ĭn-sān ]


Of, exhibiting, or afflicted with insanity.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.