A false or irrational belief held by a person despite evidence to the contrary.

False belief regarding the self or persons or objects outside the self that persists despite the facts, and is not considered tenable by one's associates.

False belief, based on incorrect inference about external reality, that is firmly held despite objective and obvious contradictory proof or evidence and despite the fact that other members of the culture do not share the belief.

False personal beliefs held contrary to reality, despite contradictory evidence and common sense.

Firmly held, illogical belief that is unsupported by evidence, and not shared by a sub-cultural group, with which a person is preoccupied.

A false belief regarding the self or persons or objects outside the self that persists despite the facts, and is not considered tenable by one's associates.

A delusion is a fixed false belief held despite evidence to the contrary. The term delusion broadly encompasses all false judgments that possess the following external characteristics to a significant, albeit unspecified, extent: (1) they are held with an exceptional level of conviction, accompanied by an unparalleled subjective certainty; (2) there is an inability to consider alternative experiences or compelling counter-arguments; (3) the content of the belief is impossible.

A disorder characterized by false personal beliefs held contrary to reality, despite contradictory evidence and common sense.

Delusion, in psychology, a rigid system of beliefs with which a person is preoccupied and to which the person firmly holds, despite the logical absurdity of the beliefs and a lack of supporting evidence. Delusions are symptomatic of such mental disorders as paranoia, schizophrenia, and major...