defense mechanism

American  

noun

1. Physiology. the defensive reaction of an organism, as against a pathogenic microorganism.

2. Psychology. an unconscious process, as denial, that protects an individual from unacceptable or painful ideas or impulses.

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defense mechanism Cultural  

1. In psychology, a Freudian term referring to an unconscious avoidance of something that produces anxiety or some other unpleasant emotion. For example, someone who blots out the memory of a terrible accident is using a defense mechanism. Regression and sublimation are common defense mechanisms.

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Etymology

Origin of defense mechanism

First recorded in 1890–95

Example Sentences

Together, the findings reveal a previously unknown natural defense mechanism within the human body.

From Science Daily • Mar. 3, 2026

For Divon, Pallywood is less a conspiracy theory than a psychological defense mechanism.

From Slate • May 30, 2025

“It was a defense mechanism because of my past history.”

From Salon • Apr. 27, 2025

Scientists believe that algae use bioluminescence as a defense mechanism — to scare off hungry sea creatures or call attention to their location, which draws the predators’ predators.

From Los Angeles Times • Oct. 30, 2024

We had created this idea of ourselves as a defense mechanism to survive in the world we were living in.

From "Born a Crime: Stories from a South African Childhood" by Trevor Noah