adversarial

adjective

ad·​ver·​sar·​i·​al ˌad-vər-ˈser-ē-əl 

ˌad-və-, 

-ˈse-rē-

: involving two people or two sides who oppose each other : of, relating to, or characteristic of an adversary or adversary procedures (see adversary entry 2 sense 2)

an adversarial relationship

an adversarial system of justice with prosecution and defense opposing each other

Synonyms of adversarial

• hostile
• negative

Examples of adversarial in a Sentence

an adversarial system of justice with prosecution and defense opposing each other

the relationship between the president and the congress should not be adversarial if anything is to get done

Recent Examples on the Web

For the latter category, the most effective results would probably come from a platform getting close to an adversarial spacecraft via what’s known as rendezvous and proximity operations (RPOs). — Mary Randolph, Scientific American, 29 Sep. 2026

The event aims to inject some levity into an historically adversarial relationship, reminding both sides of the spirit of the game. — Los Angeles Times, 29 Sep. 2026

Yet the episode also offered evidence of how natural resources provide a bulwark against an adversarial White House. — Alexis Akwagyiram, semafor.com, 21 Sep. 2026

Historically, adversarial nation-states were largely considered the biggest cybersecurity threat to critical infrastructure. — Justine Calma, The Verge, 20 Sep. 2026

Word History

Etymology

adversary entry 1 + -al entry 1

First Known Use

1839, in the meaning defined above

Rhymes for adversarial

• biserial
• filarial
• malarial
• subaerial
• actuarial
• secretarial
• urticarial
• aerial
• areal
• ariel
• burial
• antimalarial

Kids Definition

adversarial

adjective

ad·​ver·​sar·​i·​al ˌad-vər-ˈser-ē-əl 

: involving two people or two sides who oppose each other

Legal Definition

adversarial

adjective

ad·​ver·​sar·​i·​al ˌad-vər-ˈser-ē-əl 

: of, relating to, or characteristic of an adversary or adversary procedures : adversary