Instinctive, a.
Etymology: [Cf. F. instinctif.]
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.
Shades of meaning
Fernald has no entry of its own for instinctive; he lists it under spontaneous.
He lists it without comment; the entries above explain its neighbors.