insane

Meanings

1. 1
   adj

   afflicted with or characteristic of mental derangement

   was declared insane

2. 2
   adj

   Exhibiting unsoundness or disorder of mind; not sane; utterly mad.

   What is the cause of insanity? Nobody can answer such a sweeping question as that, but we know that certain diseases, such as syphilis, break down and destroy the brain cells and result in insanity. In fact, about one-half of all mental diseases can be attributed to such physical causes as brain lesions, alcohol, toxins, and injuries. But the other half—and this is the appalling part of the story—the other half of the people who go insane apparently have nothing organically wrong with their brain cells. In post-mortem examinations, when their brain tissues are studied under the highest-powered microscopes, they are found to be apparently just as healthy as yours and mine. Why do these people go insane?

3. 3
   adj

   Used by or relating to insane people.

   an insane hospital

4. 4
   adj

   Causing insanity or madness.

   Were such things here, as we doe speake about? / Or haue we eaten on the insane Root, / That takes the Reason Prisoner?

5. 5
   adj

   Characterized by excess or the utmost folly; ridiculous; impractical.

   an insane plan

6. 6
   adj

   Extremely good; incredibly amazing.

   That guy is insane at FPS games.

7. 7
   adj

   very foolish

8. 8
   adj

   Enraged; furious.

Etymology

From Latin īnsānus (“unsound in mind; mad, insane”), from in- + sānus (“sound, sane”), equivalent to in- + sane.