Definition of: idiocy

(id′ē·ə·sē) noun plural ·cies
1. The condition of being an idiot; mental deficiency amounting almost to total absence of understanding, caused by non–development or abnormality of the brain tissue.
2. Psychiatry The lowest grade of mental capacity and intelligence, often accompanied by physical abnormalities.
3. An idiotic utterance or act. [<IDIOT] Synonyms: fatuity, folly, foolishness, imbecility, incapacity, senselessness, stupidity. Idiocy is a state of mental deficiency amounting almost or quite to total absence of understanding. Imbecility is a condition of mental weakness, which incapacitates for the serious duties of life. Incapacity, or lack of legal qualification for certain acts, necessarily results from imbecility, but may also result from other causes, as from insanity or from age, sex, etc.; as, the incapacity of a minor to make a contract. Idiocy or imbecility is deficiency of mind, while insanity is disorder or abnormal action of the brain. Folly and foolishness denote a want of mental and often of moral balance. Fatuity is sometimes used as equivalent to idiocy, but more frequently signifies conceited and excessive folly. Stupidity is dulness and slowness of mental action which may range all the way from lack of normal readiness to absolute imbecility. Compare INSANITY.