knee jerk

¹

noun

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

knee-jerk

²

[ nee-jurk ]

adjective

1. of or relating to a knee-jerk.
2. Informal. reacting according to a certain habitual manner; unthinking:

   a knee-jerk liberal.

knee jerk

noun

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

adjective

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

   kneejerk support

Word History and Origins

Origin of knee jerk¹

First recorded in 1875–80

Origin of knee jerk²

First recorded in 1895–1900

Example Sentences

As you may know, Sundog has a knee jerk aversion to athleticism and technology.

From Outside Online

It is not a knee-jerk response to a sudden perceived threat.

From The Daily Beast

This whole thing about a black-and-white culture of knee-jerk reactions is reinforced by television.

From The Daily Beast

The knee-jerk cynicism with which it has been greeted is dysfunctional.

From The Daily Beast

Stop with the knee jerk, blind defense of your own side—regardless of which that may be.

From The Daily Beast

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

From The Daily Beast

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

From Project Gutenberg

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

From Project Gutenberg

Cross the knee to be stimulated over the other leg, and tap the tendon just below the knee cap, and the knee jerk appears.

From Project Gutenberg

Anxious attention to the knee jerk inhibits it; gritting the teeth or clenching the fist reinforces it.

From Project Gutenberg

We see excellent examples of cerebral facilitation and inhibition in the case of the knee jerk.

From Project Gutenberg