obsolete: impelled by an inner or animating or exciting agency
: profoundly imbued :infused<my mood, instinct with romance — S. J. Perelman>
First Known Use of INSTINCT
Medical Definition of INSTINCT
: 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
Involuntary response by an animal, resulting in a predictable and relatively fixed behaviour pattern. Instinctive behaviour is an inherited mechanism that serves to promote the survival of an animal or species. It is most apparent in fighting and sexual activity. The simplest form is the reflex. All animals have instinct, but, in general, the higher the animal form, the more flexible the behaviour. Among mammals, learned behaviour often prevails over instinctive behaviour.