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.

---

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.

---

Etymology

Origin of defense mechanism

First recorded in 1890–95

Example Sentences

Instead, seno-differentiation appears to serve as a stress-triggered defense mechanism that removes damaged stem cells before they can become harmful.

From Science Daily • Oct. 25, 2025

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

From Slate • May 30, 2025

I think it’s sort of her defense mechanism — if I get there first, no one can get to it before me.

From Los Angeles Times • Nov. 21, 2024

“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

It just about shattered every defense mechanism and every pretext I had against going to school.

From "Kaffir Boy: An Autobiography" by Mark Mathabane