spontaneous, impulsive, instinctive, automatic, mechanical mean acting or activated without deliberation. spontaneous implies lack of prompting and connotes naturalness.

INSTINCTIVE definition: of, relating to, or of the nature of instinct. See examples of instinctive used in a sentence.

Not expected or planned (Definition of instinctive from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)

Being such by natural inclination rather than conscious effort or study: "Both men were instinctive masters at seizing unexpected openings and turning them into victories" (Nick Kotz).

Definition of instinctive adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Arising from impulse or natural inclination; done without thought or conscious effort; spontaneous. An instinctive sympathy for the downtrodden.

An instinctive feeling, idea, or action is one that you have or do without thinking or reasoning. It's an absolutely instinctive reaction–if a child falls you pick it up.