/ Thesaurus / K Synonyms of knee jerk Find synonyms for: Noun1. knee jerk, knee-jerk reflex, patellar reflex, reflex, reflex response, reflex action, instinctive reflex, innate reflex, inborn reflex, unconditioned reflex, physiological reactionusage: a reflex extension of the leg resulting from a sharp tap on the patellar tendonWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language