Instinct

Etymology

From Latin "instinctus" (impulse, instigation), from "instinguere" (to incite, impel), related to "stinguere" (to prick). The buried image is of being goaded from within — an inner prick that drives action before thought has any say.

noun · /IN-stinkt/
An innate, unlearned pattern of behavior or an automatic impulse to act.
What it names
Behavior that comes pre-installed — no training required — the biological floor beneath all our learned responses.
Example
The newly hatched turtles headed for the ocean on pure instinct, with no parent to show them the way.
Related idea
Instinct is innate and shared across a species, present from birth; intuition is a fast judgment shaped by personal experience — instinct is inherited, intuition is learned and then automatic.