Meaning of insanity

in•san•i•ty

Pronunciation: (in-san'i-tē), [key]
— pl. -ties.
  1. the condition of being insane; a derangement of the mind.
  2. such unsoundness of mind as affects legal responsibility or capacity.
  3. (formerly) psychosis.
  4. extreme folly; senselessness; foolhardiness.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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