knee-jerk

adjective \ ˈnē-ˌjərk , -ˈjərk \
|Updated on: 16 Jul 2018

Definition of knee-jerk

: readily predictable : automatic
  • knee-jerk reactions
; also, disapproving : reacting in a readily predictable way
  • The man was such a bleeding-heart knee-jerk liberal that you could predict the rest of the column after reading the first sentence.
  • —Andrew M. Greeley

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First Known Use of knee-jerk

1958

in the meaning defined above

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knee jerk

noun

Definition of knee jerk

: an involuntary forward kick produced by a light blow on the tendon below the patella

Recent Examples of knee jerk from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'knee jerk.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of knee jerk

1849

in the meaning defined above

See Words from the same year
NEW! Time Traveler

KNEE-JERK Defined for English Language Learners

knee-jerk

Definition of knee-jerk for English Language Learners

  • : occurring quickly and without thought

  • : often reacting quickly and without thought


Medical Dictionary

knee jerk

noun

medical Definition of knee jerk

: an involuntary forward jerk or kick produced by a light blow or sudden strain upon the patellar tendon of the knee that causes a reflex contraction of the quadriceps muscle called also patellar reflex


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