instinctual

done instantly and without conscious thought or decision the birds' instinctual response is to fly away when startled Synonyms instinctive, automatic, involuntary, knee-jerk, mechanic, mechanical, robotic, spontaneousRelated Words conditioned, natural, Pavlovian, reactive, reflex, simple, subliminal, unconscious, unforced, visceral; blind, inadvertent, unintended, unintentional, unwilling, unwitting; abrupt, quick, ready, sudden; ad-lib, extemporaneous, extempore, impromptu, improvised, offhand, offhanded, off-the-cuff, snap, spur-of-the-moment, unconsidered, unplanned, unpremeditated, unprepared, unprompted, unreasoned, unrehearsed, unstudied; casual, chance, chancy, haphazard, hasty, hit-or-miss, impetuous, impulsive, mindless, random, rashNear Antonyms calculated, conscious, cultivated, deliberate, designed, intended, intentional, predetermined, prepared, projected, refined, rehearsed, volitional, voluntary, willed, willful (or wilful); advised, aforethought, careful, considered, foresighted, forethoughtful, measured, meticulous, reasoned, studied, thoughtfulAntonyms nonmechanical