1
: a plea of justification for the use of force or for homicide
2
: the act of defending oneself, one's property, or a close relative

Examples of self-defense in a Sentence

Recent Examples on the Web
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Members of a local self-defense citizens brigade eventually intervened by firing warning shots into the air to stop the attack. Jacqueline Charles, Miami Herald, 3 Sep. 2026 But the industry lags overall due to a constitutional limit on the use of force for only its own self-defense. Mia Osmonbekov, Fortune, 31 Aug. 2026 In a moment of self-defense, Brian stabbed and killed Malcolm right in front of Ellen, a violent escalation that has now complicated the start of their life together (as if the rebellion wasn’t enough). Max Gao, HollywoodReporter, 31 Aug. 2026 The former officer also made a different self-defense claim on the night of the shooting, according to grand jury testimony. Richard Winton, Los Angeles Times, 31 Aug. 2026 See All Example Sentences for self-defense

Word History

First Known Use

1609, in the meaning defined at sense 2

Time Traveler
The first known use of self-defense was in 1609

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Cite this Entry

“Self-defense.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/self-defense. Accessed 7 Sep. 2026.

Kids Definition

self-defense

noun
self-de·​fense
ˌself-di-ˈfen(t)s
: the act of defending oneself, one's property, or a close relative

Legal Definition

self-defense

noun
self-de·​fense
ˈself-di-ˈfens
1
: the use of force to defend oneself
2
: an affirmative defense (as to a murder charge) alleging that the defendant used force necessarily to protect himself or herself because of a reasonable belief that the other party intended to inflict great bodily harm or death see also justification sense 2

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