adversary

American  

[ad-ver-ser-ee] / ˈæd vərˌsɛr i /

noun

plural

adversaries

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

Related Words

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

• adversariness
  noun
• nonadversarial
  adjective

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

That distinction matters most when an adversary seeks a rapid fait accompli—a limited territorial gain achieved before the U.S. can respond effectively.

From The Wall Street Journal • May 3, 2026

Wary of China's navy build-up, US ally Australia has reshaped its defence force in recent years to focus on its missile strike capability and deterring an adversary from its northern approaches.

From Barron's • Apr. 14, 2026

Those tensions are already in play between the U.S. and its biggest adversary, China, which has been no slouch when it comes to space exploration.

From Salon • Apr. 9, 2026

Now the US finds itself in a different kind of race with a different adversary: China.

From BBC • Apr. 7, 2026

The grenadiers, six by six, marched straight toward our adversary.

From "The Astonishing Life of Octavian Nothing, Traitor to the Nation, Volume II: The Kingdom on the Waves" by M.T. Anderson

Related Words

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