- The definition of insanity is having a serious mental illness or being extremely foolish.
- An example of insanity is a personality disorder.
- An example of insanity is jumping out of an airplane without a parachute.
insanity definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
noun pl. insanities
- the state of being insane; mental illness or derangement, usually excluding amentia: not a technical term
- Law any form or degree of mental derangement or unsoundness of mind, permanent or temporary, that makes a person incapable of what is regarded legally as normal, rational conduct or judgment: it usually implies a need for hospitalization
- great folly; extreme senselessness
Origin: Classical Latin insanitas ; from insanus
insanity definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
noun pl. in·san·i·ties
- Mental illness or derangement. No longer in scientific use.
- Law a. Unsoundness of mind sufficient in the judgment of a civil court to render a person unfit to maintain a contractual or other legal relationship or to warrant commitment to a mental health facility.b. In most criminal jurisdictions, a degree of mental malfunctioning sufficient to relieve the accused of legal responsibility for the act committed.
- a. Extreme foolishness; folly.b. Something that is extremely foolish.
insanity - Ologies & -Isms Definition
Ologies & -Isms. Copyright 2010 The Gale Group, Inc. All rights reserved.
abalienation Obsolete, insanity. acromania a violent form of mania; incurable insanity. amentia 1. a congenital condition of low intelligence. 2. a form of temporary insanity. Cf. dementia. amenty Obsolete, amentia. bedlamism behavior characteristic of insanity. See also order and disorder. bedlamite a mental patient. catatonia one of various forms of schizophrenia characterized by stupor, sometimes alternating with excited behavior and mechanical, repetitive behavior, accompanied by muscular rigidity. —catatonic, n., adj. delirium a state of maniacal excitement characterized by restless behavior, confused speech, and sometimes hallucinations. dementia madness or insanity. Cf. amentia. dementia praecox schizophrenia. demonianism 1. Obsolete, the doctrine of demoniac possession. 2. Archaic. demonomania. —demonian, n., adj. demonomania Medicine. a monomania in which a person believes he is possessed of devils. Also called demonopathy. diabolepsy Medicine, Obsolete, a state in which a person believes he is possessed by a devil or has been endowed with supernatural powers. hallucinosis a disordered mental condition in which the sufferer is prone to hallucinations. hebephrenia a form of insanity or dementia praecox that can appear at puberty, characterized by foolish behavior and deterioration of the mental faculties. hypermania an acute mania. lunacy 1. periodic insanity, once thought to be caused by the phases of the moon. 2. any form of insanity. —lunatic, adj. lypemania an abnormal tendency toward deep melancholy. lyssophobia an abnormal fear of becoming insane. maniaphobia an abnormal fear of madness. megalomania 1. Medicine. a form of mental illness characterized by the unreasonable conviction in the patient of his own greatness, goodness, power, or wealth. 2. an obsession with extravagant or grand actions. — megalomaniac, n., adj. —megalomaniacal, adj. melancholia a condition of abnormal gloom or depression, often of an intensity to become a form of insanity. —melancholiac, n., adj. —melancholie, n., adj. melancholian Obsolete, a person suffering from melancholia; a melancholiac. narcosynthesis a form of treatment for mental illness that involves placing the patient under the influence of a narcotic. orthosis the process of correcting bodily or mental distortion. paranoia a mental disorder characterized by behavior that stems from an elaborately constructed system of delusions of persecution and grandeur. —paranoiac, n. —paranoid, adj. paranoidism a state resembling paranoia. pathomania moral insanity. psychosis any severe mental disorder or disease. —psychotic, n., adj. schizophrenia a psychotic condition marked by erratic behavior, withdrawal from reality, and intellectual and emotional deterioration. Also called dementia praecox. —schizophrenic, n., adj. schizothymia a mild form of schizophrenia, characterized by withdrawal, inversion, etc. —schizothyme, n. —schizothymic, adj. submania a mild mania. zoanthropy a form of insanity or mental disorder in which the sufferer imagines that he is an animal. —zoanthropic, adj. zoopsia a form of hallucination in which the sufferer imagines he sees animals. Also called zooscopy. zooscopy zoopsia.
insanity - Legal Definition
Webster's New World Law Dictionary Copyright © 2010 by Wiley Publishing, Inc., Hoboken, New Jersey. Used by arrangement with John Wiley & Sons, Inc.
A mental disorder that deprives a criminal defendant of capacity to be tried.
insanity - Medical Definition
- Persistent mental disorder or derangement. Not in scientific use.
- Unsoundness of mind sufficient in the judgment of a civil court to render a person unfit to maintain a contractual or other legal relationship or to warrant commitment to a mental health facility.
- In most criminal jurisdictions, a degree of mental malfunctioning considered to be sufficient to relieve the accused of legal responsibility for the act committed.