de·fense
di-ˈfen(t)s 
as antonym of "offense" often
ˈdē-ˌfen(t)s
1
a
: the act or action of defending
the defense of our country
speak out in defense of justice
quickly jumped to her friend's defense
b
law
: the denial, answer, or plea (see plea sense 2b) of one against whom a criminal or civil action is brought : a defendant 's denial, answer, or plea
2
a
: capability of resisting attack
the body's defense against disease
b
sports
: ability to keep an opponent from scoring in a game or contest : defensive play or ability
a player known for good defense
3
a
: means or method of defending or protecting oneself, one's team, or another
the nation's air and ground defenses
Big shells are an effective defense against these predators as well.—
Gregory P. Dietl
Gregory P. Dietl
also
: a defensive structure
b
: an argument in support or justification
offered no defense of his actions
c
law
: the collected facts and method adopted by a defendant to protect and defend against a plaintiff's action
His lawyers used an insanity defense.
d
chess
: a sequence of moves available to the second player in the opening (see opening sense 3a)
4
a
law
: a defending party or group (as in a court of law)
The defense rests.
b
sports
: a defensive team
He was the linchpin of one of the league's stoutest defenses …—Sarah Kwak
Sarah Kwak
defensed; defensing
sports
: to take specific defensive action against (an opposing team or player or an offensive play) : to attempt to keep (an opponent or play) from scoring in a game or contest
The gangly Pressey was clearly Milwaukee's only real hope of defensing Bird …—Jack McCallum
Jack McCallumExamples of defense in a Sentence
Noun
They put up a good defense, but the city ultimately fell to the invaders.
They mounted a good defense.
The city's defenses were not strong enough to keep out the invaders.
We need to improve our defenses.
the nation's air and ground defenses
Recent Examples on the Web
Reuters, NBC news, 31 Oct. 2025
Buffalo’s defense dominated in last week’s 40-9 rout of the Carolina Panthers but suffered another setback, losing Ed Oliver to a torn bicep.
—Andy Scholes, CNN Money, 30 Oct. 2025
Seth Emerson, New York Times, 7 Oct. 2025
Armenia had been thoroughly routed, its aged defenses no match for the much larger Azerbaijan’s Israeli drones, vast wealth, and modernized military.
—Brady Knox, The Washington Examiner, 21 Sep. 2025
See All Example Sentences for defense
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Noun
Lai has pledged to increase military spending to 5% of GDP by 2030, strengthening the island’s defenses in the face of a rising threat from its giant neighbor China.
—Reuters, NBC news, 31 Oct. 2025
Buffalo’s defense dominated in last week’s 40-9 rout of the Carolina Panthers but suffered another setback, losing Ed Oliver to a torn bicep.
—Andy Scholes, CNN Money, 30 Oct. 2025
Verb
And just as importantly, in the All-American tight end and immediate NFL star, Georgia had a clear go-to receiver, the one its quarterback could look to in key moments, who defenses had to worry about, and thus opened the field for other receivers.
—Seth Emerson, New York Times, 7 Oct. 2025
Armenia had been thoroughly routed, its aged defenses no match for the much larger Azerbaijan’s Israeli drones, vast wealth, and modernized military.
—Brady Knox, The Washington Examiner, 21 Sep. 2025
See All Example Sentences for defense
Cite this Entry
“Defense.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/defense. Accessed 4 Nov. 2025.
Copy CitationMedical Definition
defense
noun
de·fense
variants
or chiefly British defence
: a means or method of protecting the physical or functional integrity of body or mind
ability to concentrate urine may be interpreted as a renal defense of body volume fluid—Jack Metcoff
Jack MetcoffLegal Definition
defense
noun
de·fense
di-ˈfens, ˈdē-ˌfens
1
: the act or action of defending see also self-defense
2
a
: the theory or ground that forms the basis for a defendant's opposition to an allegation in a complaint or to a charge in a charging instrument (as an indictment)
also
: the evidence and arguments presented supporting the defendant's opposition see also accord, alibi, assumption of risk, coercion, consent, contributory negligence at negligence, denial, diminished capacity, duress, entrapment, estoppel, fraud, infancy, insanity, intoxication, laches, mistake, necessity, res judicata, statute of limitations
—
absolute defense
: complete defense in this entry
—
affirmative defense
: a defense that does not deny the truth of the allegations against the defendant but gives some other reason (as insanity, assumption of risk, or expiration of the statute of limitations) why the defendant cannot be held liable
Note: The defendant bears the burden of proof as to affirmative defenses.
—
choice of evils defense
: a defense to a criminal charge based on the assertion that the criminal act was committed to avoid the commission of an even greater evil
called also lesser evils defense
Note: In jurisdictions that recognize the choice of evils defense, it encompasses both of the older defenses of duress and necessity.
—
complete defense
: a defense that shields the defendant from any liability and bars any recovery by the plaintiff compare partial defense in this entry
—
lesser evils defense
: choice of evils defense in this entry
—
meritorious defense
: a defense that is based on evidence sufficient to warrant setting aside a default judgment against the defendant in civil litigation
—
partial defense
: a defense by which the defendant reduces the amount of damages of which he or she is liable compare complete defense in this entry
b
: a basis upon which an obligor of a negotiable instrument may avoid liability under the instrument
—
personal defense
: a defense of an obligor under a negotiable instrument that can be asserted against anyone but a holder in due course
—
real defense
: a defense of an obligor of a negotiable instrument that may be asserted even against a holder in due course
Note: Section 3-305(a)(1) of the Uniform Commercial Code sets out the real defenses as infancy, duress, lack of legal capacity, illegality of the transaction, fraud in the factum, and discharge of the obligor by a bankruptcy court. By exclusion, all other defenses are personal defenses.
3
: the defending side in a legal proceeding
the defense rests
compare prosecution
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