Noun, pl. instincts
1. The inherent inclination of a living organism toward a particular complex behavior. (wikipedia.org)
2. A natural or inherent impulse or behaviour (wiktionary.org).
3. An intuitive reaction not based on rational conscious thought. (wiktionary.org)
4. An inborn pattern of behavior that is characteristic of a species and is often a response to specific environmental stimuli (thefreedictionary.com)
5. An innate, typically fixed pattern of behavior in animals in response to certain stimuli. (Google Dictionary)
Syn: Innate behavior
Word origin: From Latin instinctus “instigation, impulse,” noun use of past participle of instinguere “to incite, impel,” from in– “on” + stinguere “prick, goad.”