Synonyms for Reflex (same or very similar meaning)
WordNet sense 1 (without volition or conscious control):
automatic, reflexive
WordNet sense 2 (controlled by the autonomic nervous system; without conscious control):
involuntary
WordNet sense 3 (an automatic instinctive unlearned reaction to a stimulus):
inborn reflex, innate reflex, instinctive reflex, physiological reaction, unconditioned reflex
From the ODE community, based on WordNet
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