Learn English idioms with meanings and examples

🌎Region: International πŸ“ŠDifficulty Level:intermediate

knee-jerk reaction

An automatic, quick reaction made without careful thought; often impulsive or habitual.

From the medical β€œknee-jerk” reflex (patellar reflex), where a tap below the knee makes the leg kick involuntarily; metaphorically applied to unthinking responses.

Often mildly critical: it implies an unthinking, reflexive response rather than a considered decision. Common in politics, business, and commentary.

  • His knee-jerk reaction was to blame his assistant, but later he realized it was his mistake.
  • The company issued a knee-jerk reaction to the criticism and walked it back the next day.
  • Try not to have a knee-jerk reaction when you read that email; take a minute to cool down.
  • Banning phones outright is a knee-jerk reaction that ignores why students use them.
  • Her knee-jerk reaction to any change is to say no, even before hearing the plan.

Usually a noun phrase: β€œa knee-jerk reaction (to X).” Also used attributively: β€œa knee-jerk response,” β€œknee-jerk opposition.” Hyphenated as an adjective (knee-jerk).

  • reflex reaction
  • automatic response
  • impulsive reaction
  • snap reaction
  • considered response
  • measured response
  • thoughtful decision