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

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

On Friday night, Cronin and the Bruins will take on the challenge of Central Florida and his longtime adversary Dawkins, mindful there are no gimmes once you get this far.

From Los Angeles Times • Mar. 20, 2026

Washington, once an adversary, now describes a "wonderful" relationship, citing some political prisoner releases and new oil and mining deals.

From BBC • Mar. 17, 2026

One cannot best an adversary without full awareness of said adversary’s strengths.

From "Odd One Out" by Nic Stone

Related Words

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