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

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

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

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.

Definition of instinctive adjective from the Oxford Advanced Learner's Dictionary. based on instinct (= a natural quality that makes somebody/something behave in a particular way), not thought …

Instinct is the inherent inclination of a living organism towards a particular complex behaviour, containing innate (inborn) elements. The simplest example of an instinctive behaviour is a …

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).

INSTINCTIVE meaning: relating to or based on instinct based on feelings or desires that do not come from thinking or learning

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

done or felt without thinking or considering: an instinctive feeling of distrust; Babies have an instinctive fear of falling. done or performed by instinct: instinctive mating patterns.