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

Experts say rattlesnakes typically don’t bite unless they feel threatened and use their bite as a defense mechanism.

From Los Angeles Times • Apr. 7, 2026

Inflammation is an essential defense mechanism that protects us from infection and injury.

From Science Daily • Feb. 19, 2026

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

From Slate • May 30, 2025

“I’m ready to take care of business, as a defense mechanism, because it’s gotten to the point where you have to take some responsibility for your own safety.”

From Los Angeles Times • May 9, 2024

But then my body took over and this primal defense mechanism, said, No, we will not stand for this.

From "Dumplin'" by Julie Murphy