# knee-jerk reaction

idiom

Source: https://englishreference.com/idiom/knee-jerk-reaction
Updated: 2026-08-10

## Meaning

An instantaneous reaction made without thought.

## Examples

- Do not make a knee-jerk reaction to the bad news.
- You should avoid a knee-jerk reaction when you receive an angry email.
- The manager made a knee-jerk reaction to the low sales figures by firing the entire marketing team.
- When the website crashed, the owner had a knee-jerk reaction and deleted the entire database instead of waiting for the technician.
- The government’s knee-jerk reaction to the protest was to ban all public gatherings, which only made the citizens more upset.
- Rather than offering a thoughtful solution, the committee provided a knee-jerk reaction that failed to address the underlying complexities of the policy change.

## Origin

The term emerged as an elliptical reference to the patellar reflex, an involuntary movement of the lower leg produced by the stimulation of a reflex arc. The physiological action involves a sharp tap to the tendon below the kneecap, resulting in a response that requires no intervention from the brain. By the early 20th century, the physical phenomenon was applied figuratively to describe an immediate and unthinking intellectual response.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.