Definition of knee-jerk
(Entry 1 of 2)
: 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
knee jerk
noun
Definition of knee jerk (Entry 2 of 2)
: an involuntary forward kick produced by a light blow on the tendon below the patella
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Merriam-Webster unabridged
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The first known use of knee-jerk was in 1849
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