Used chiefly in criminal law, this term means an impulse to commit an unlawful or criminal act which cannot be resisted or overcome by the patient because insanity or mental disease has destroyed the freedom of his will and his power of self-control and of choice as to his actions. See McCarty v. Com., 114 Ky. 620, 71 S. W. 058; State v. Knight, 95 Me. 467, 50 Atl. 276, 55 L. R. A. 373; Leache v. State, 22 Tex. App. 279, 3 S. W. 539, 58 Am. Rep. 638; State v. Peel, 23 Mont. 358, 59 Pac. 169, 75 Am. St. Rep. 529. And see INSANITY.