instinct /ˈɪn.stɪŋkt/noun 2adjective 1forms 3phrases 1 noun2 •a way of acting that a person or animal is born with and does not have to learnMany animals fear fire by instinct. •An intuitive reaction not based on rational conscious thought.Debbie's instinct was to distrust John. adjective1 •(no longer used) Imbued, charged (with something).The chariot of paternal deity […] / Itself instinct with spirit, but convoyed / By four cherubic shapes. — 1667 formsinstincts · more instinct · most instinct Phrases with instinct killer instinctThe natural inclination to aggressively achieve dominance or success in a particular endeavor.