dementia Meaning, Definition & Usage

  1. noun mental deterioration of organic or functional origin
    dementedness.

WordNet

De*men"ti*a noun
Etymology
L., fr. demens. See Dement.
Definitions
  1. Insanity; madness; esp. that form which consists in weakness or total loss of thought and reason; mental imbecility; idiocy.

Webster 1913