Definition of: instinct

(in′stingkt) noun
1. A natural impulse or innate propensity that incites animals (including man) to the actions that are essential to their existence, preservation, and development; animal intuition.
2. Psychol. a A strong, innate tendency to certain actions and forms of behavior, often accompanied by emotional excitement. b A complex, unlearned, adaptive response to some situation or experience.
3. A natural aptitude.
—adjective (in·stingkt′) Animated from within; moved by or imbued with inward impulse; filled; alive: usually with with. [<L instinctus, pp. of instinguere impel]