INSTINCT

I. noun Etymology: Middle English, from Latin ~us impulse, from instinguere to incite; akin to Latin instigare to instigate Date: 15th century a natural or inherent aptitude, impulse, or capacity , 2. a largely inheritable and unalterable tendency of an organism to make a complex and specific response to environmental stimuli without involving reason, behavior that is mediated by reactions below the conscious level, ~ual adjective ~ually adverb II. adjective Date: 1667 impelled by an inner or animating or exciting agency, profoundly imbued ; infused