INSTINCTIVE
natural, instinctive
(adjective) unthinking; prompted by (or as if by) instinct; “a cat’s natural aversion to water”; “offering to help was as instinctive as breathing”
Source: WordNet® 3.1
Etymology
Adjective
instinctive (comparative more instinctive, superlative most instinctive)
Related to or prompted by instinct.
Driven by impulse, spontaneous and without thinking.
Source: Wiktionary
In*stinc"tive, a. Etym: [Cf. F. instinctif.]
Definition: Of or pertaining to instinct; derived from, or prompted by,
instinct; of the nature of instinct; determined by natural impulse or
propensity; acting or produced without reasoning, deliberation,
instruction, or experience; spontaneous. "Instinctive motion."
Milton. "Instinctive dread." Cowper.
With taste instinctive give Each grace appropriate. Mason.
Have we had instinctive intimations of the death of some absent
friends Bp. Hall.
Note: The terms instinctive belief, instinctive judgment, instinctive
cognition, are expressions not ill adapted to characterize a belief,
judgment, or cognition, which, as the result of no anterior
consciousness, is, like the products of animal instinct, the
intelligent effect of (as far as we are concerned) an unknown cause.
Sir H. Hamilton.
Syn.
– Natural; voluntary; spontaneous; original; innate; inherent;
automatic.
Source: Webster’s Unabridged Dictionary 1913 Edition