Meaning of INSANITY in English


ə̇nˈsanəd.ē, -ətē, -i noun

Etymology: Latin insanitas, from insanus insane + -itas -ity


a. : the state of being insane : unsoundness or derangement of the mind usually occurring as a specific disorder (as schizophrenia or dementia praecox) and usually excluding such states as mental deficiency, the psychoneuroses, and various character disorders

b. : a mental disorder

dementia praecox is one of the commoner insanities

2. : such unsoundness of mind or lack of understanding as prevents one from having the mental capacity required by law to enter into a particular relationship, status, or transaction or as excuses one from criminal or civil responsibility


a. : extreme folly or unreasonableness

the insanity of war

b. : something utterly foolish or unreasonable

the insanities of daily life


lunacy , psychosis , mania , dementia : insanity , more commonly used in law than in medicine, applies to any mental disorder of such severity as to render the person unfit to manage his own affairs or to enjoy his liberty because of the unreliability of his behavior that makes him a danger to himself and to others. lunacy , a term legally interchangeable with insanity, popularly implies periodic mental disorder or alternating madness and lucidity. psychosis is the technical psychiatric term for any far-reaching and prolonged behavior disorder (as dementia praecox or manic-depressive psychosis). mania is a phase of a mental disorder (as manic-depressive psychosis) marked by a mood of sustained and exaggerated elation, emotional expansiveness, overtalkativeness, excessive physical activity, or delusions of greatness, that characterizes any of several psychoses. dementia is the technical psychiatric term that denotes mental deterioration that is psychogenic in origin (as dementia praecox) or that results from disease that damages the brain substance (as neurosyphilis or arteriosclerosis)

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.