knee jerk: Meaning and Definition of
- a reflex extension of the leg, caused by contraction of the quadriceps, resulting from a sharp tap on the patellar tendon; patellar reflex.
Pronunciation: (nē'jûrk"), [key]
- of or pertaining to a knee-jerk.
- reacting according to a certain habitual manner; unthinking: a knee-jerk liberal.