defense mechanism

noun

1

: an often unconscious mental process (such as repression) that makes possible compromise solutions to personal problems

2

: a defensive reaction by an organism

Examples of defense mechanism in a Sentence

She is projecting her anger on you as a defense mechanism.

the cell's normal defense mechanisms against infection

Recent Examples on the Web

Bernstein says that instinct is likely a defense mechanism. —Erica Sweeney, Time, 26 Mar. 2025

Challenges of detecting resistance Antimicrobial resistance is a natural process where microbes constantly evolve as a defense mechanism, acquiring genetic changes that enhance their survival. —Nneka Vivian Iduu, The Conversation, 24 Mar. 2025

Now, scientists have discovered a surprising new technique that appears to be a defense mechanism: Some male octopuses use venom to avoid being eaten by their female mates. —Sarah Kuta, Smithsonian Magazine, 11 Mar. 2025

Or is this all a defense mechanism for the heir apparent to the Eagan empire? —Josh Wigler, The Hollywood Reporter, 27 Feb. 2025

Word History

First Known Use

1909, in the meaning defined at sense 1

Rhymes for defense mechanism

• abolitionism
• aldosteronism
• americanism
• anticommunism
• antisemitism
• antiterrorism
• bioterrorism
• colloquialism
• colonialism
• consequentialism
• contextualism
• conventionalism

Medical Definition

defense mechanism

noun

1

: an often unconscious mental process (as repression, projection, or sublimation) that makes possible compromise solutions to personal problems

2

: a defensive reaction by an organism