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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Trump struck a deal Friday with NATO to send Kyiv Patriot batteries, a key defense mechanism against ballistic missiles. Amalia Huot-Marchand, The Hill, 11 July 2025 Instead of encouraging genuine intimacy, oversharing too soon can become a defense mechanism—one that covertly seeks reassurance rather than connection. Mark Travers, Forbes, 13 Mar. 2025 This size difference is likely linked to the males’ reproductive defense mechanism. Sarah Kuta, Smithsonian Magazine, 11 Mar. 2025 Real relationships, however, are the best defense against our own defense mechanisms. Shani Harmon, Forbes.com, 25 June 2025 See All Example Sentences for defense mechanism

Word History

First Known Use

1909, in the meaning defined at sense 1

Time Traveler
The first known use of defense mechanism was in 1909

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Cite this Entry

“Defense mechanism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/defense%20mechanism. Accessed 22 Jul. 2025.

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

More from Merriam-Webster on defense mechanism

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