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

"But that's not enough when the adversary is fighting what they see as an existential conflict."

From Barron's • May 11, 2026

That ecosystem worked because risk‑taking was rewarded, growth was possible, and civic leadership—while imperfect—understood that private enterprise wasn’t the adversary of the public good.

From The Wall Street Journal • May 11, 2026

"No adversary should mistake our current restraint with a lack of resolve," General Dan Caine told reporters, amid fears the current US-Iranian ceasefire is unravelling.

From Barron's • May 5, 2026

Because a blockade is recognized in international law as an act of war, governments more often characterize their efforts to isolate an adversary as sanctions, embargoes or quarantines that suggest narrower goals.

From The Wall Street Journal • Apr. 16, 2026

It was still my adversary, and I could not trust it to carry me.

From "Flying Through Water" by Mamle Wolo

Related Words

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