knee jerk

See synonyms for knee jerk on
  1. a reflex extension of the leg, caused by contraction of the quadriceps, resulting from a sharp tap on the patellar tendon; patellar reflex.

Origin of knee jerk

First recorded in 1875–80

Words Nearby knee jerk

Other definitions for knee-jerk (2 of 2)

[ nee-jurk ]

  1. of or relating to a knee-jerk.

  2. Informal. reacting according to a certain habitual manner; unthinking: a knee-jerk liberal.

Origin of knee-jerk

First recorded in 1895–1900 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use knee jerk in a sentence

  • Republicans are going to try to paint Bellows as a knee-jerk Democrat who just uses the civil-liberties argument when convenient.

  • The deep reflexes may also be altered, the knee-jerk being frequently absent on the affected side.

  • In some subjects the larger dose, 45 cubic centimeters, practically abolished the knee-jerk.

    How to Live | Irving Fisher and Eugene Fisk
  • Cross the knee to be stimulated over the other leg, and tap the tendon just below the knee cap, and the knee jerk appears.

    Psychology | Robert S. Woodworth
  • Anxious attention to the knee jerk inhibits it; gritting the teeth or clenching the fist reinforces it.

    Psychology | Robert S. Woodworth
  • We see excellent examples of cerebral facilitation and inhibition in the case of the knee jerk.

    Psychology | Robert S. Woodworth

British Dictionary definitions for knee jerk

knee jerk

  1. Also called: patellar reflex physiol an outward reflex kick of the lower leg caused by a sharp tap on the quadriceps tendon just below the patella

  1. made or occurring as a predictable and automatic response, without thought: kneejerk support

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012