adversary

American  

[ad-ver-ser-ee] / ˈæd vərˌsɛr i /

noun

adversaries plural

1. a person, group, or force that opposes or attacks; opponent; enemy; foe.

   Antonyms:

   ally

2. a person, group, etc., that is an opponent in a contest; contestant.

3. the Adversary, the devil; Satan.

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adjective

1. of or relating to an adversary.

2. involving adversaries, as plaintiff and defendant in a legal proceeding.

   an adversary trial.

adversary British  

/ ˈædvəsərɪ /

noun

1. a person or group that is hostile to someone; enemy

2. an opposing contestant in a game or sport

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adjective

1. the US term for adversarial

Synonym Usage

Adversary, antagonist mean a person or a group contending against another. Adversary suggests an enemy who fights determinedly, continuously, and relentlessly: a formidable adversary. Antagonist suggests one who, in hostile spirit, opposes another, often in a particular contest or struggle: a duel with an antagonist.

Other Word Forms

Derived Forms

• adversariness
  noun
• adversarial
  adjective
• nonadversarial
  adjective

Inflected Forms

Nouns

• adversaries
  plural

Etymology

Origin of adversary

First recorded in 1300–50; Middle English adversarie, from Latin adversārius; equivalent to adverse + -ary; replacing Middle English adversere, from Anglo-French

Explanation

An adversary is an enemy or someone who opposes someone else. In tennis, you stand across the net from your adversary. Adversary is related to the word adverse, meaning "against or contrary" — so think of an adversary as someone whom you are fighting against. If you're the undefeated chess champion, you have bested every single one of your adversaries. Adversary is derived from a Latin word meaning "against."

Example Sentences

See Examples For:

adversary adversaries

On the other side were national security officials more focused on China, who feared America could be offshoring its most powerful new source of dominance to an adversary.

From The Wall Street Journal ● Jul. 19, 2026

She has proven a formidable adversary for Democrats for 30 years, most recently defeating a better-funded opponent in 2020 despite polls showing her trailing right up to election day.

From BBC ● Jul. 9, 2026

But even with the new investment it is likely that an adversary armed with hypersonic missiles would be able to overwhelm Britain's defences.

From BBC ● Jun. 30, 2026

Pyongyang has repeatedly shunned efforts by the South Korean government to improve relations, calling Seoul its most "hostile" adversary.

From Barron's ● Jun. 5, 2026

Our involvement is not that of an adversary in a straightforward game, but more like blundering into someone else’s accident.

From "The Lives of a Cell" by Lewis Thomas

A company spokeswoman defended the steps Anthropic has taken as necessary to ensure models are safe and that adversaries can’t use them to create severe risks.

From The Wall Street Journal ● Jul. 29, 2026

Critical investments were needed to prevent adversaries from outpacing the US, he continued.

From BBC ● Jul. 22, 2026

He added, with sting as a resigning defence secretary, that "our adversaries do not follow timetables set by the Treasury."

From BBC ● Jul. 21, 2026

“The collection will visit various countries of the world for two years and will come back, as it says in the law,” Sheinbaum told reporters in April, blaming political adversaries for the contretemps.

From Los Angeles Times ● Jul. 14, 2026

So, swimming in fedock-deep slop and conceding as many as twenty-four pounds to his adversaries, Seabiscuit finished third, snapping his historic win streak.

From "Seabiscuit: An American Legend" by Laura Hillenbrand

Related Words

• antagonist
• attacker
• competitor
• enemy
• foe
• opponent
• rival