self-defense
Americannoun
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the act of defending one's person when physically attacked, as by countering blows or overcoming an assailant.
the art of self-defense.
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a claim or plea that the use of force or injuring or killing another was necessary in defending one's own person from physical attack.
He shot the man who was trying to stab him and pleaded self-defense at the murder trial.
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an act or instance of defending or protecting one's own interests, property, ideas, etc., as by argument or strategy.
Other Word Forms
- self-defensive adjective
Etymology
Origin of self-defense
First recorded in 1645–55
Explanation
When you protect yourself forcefully against an attack, that's self-defense. If you kicked a dog that tried to bite you, you don't need to feel bad: it was self-defense. The act of defending yourself, protecting yourself from being physically harmed, is self-defense. You can take a class to learn tactics of self-defense; many martial arts can be used this way, to fend off an attacker. Self-defense is also a legal right — by law, people can use "reasonable force" to defend their own lives. Self-defense was originally a sporting term, first used in fencing and then in boxing.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
This could be a Chapter IV mandate adopted by the United Nations Security Council, which includes permission to use force not just in self-defense.
From The Wall Street Journal • Apr. 14, 2026
In 1993, Jackson told Rolling Stone interviewer David Ritz that “Nasty” and “What Have You Done for Me Lately” were born out of a sense of self-defense.
From Salon • Apr. 11, 2026
Black paired up with Marcello Hernández to play martial arts instructors who teach unorthodox self-defense methods.
From Los Angeles Times • Apr. 5, 2026
One thing the Supreme Court made clear in these landmark cases, though, is that the core purpose of the Second Amendment is lawful self-defense.
From Slate • Mar. 27, 2026
First rule of self-defense is: Don’t ask your attacker for validation.
From "Maybe He Just Likes You" by Barbara Dee
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
