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

These can include sabotaging infrastructure to foment unrest, subtly interfering with training exercises to undermine Arctic capabilities, and exploiting divisions in adversarial alliances. —Tristan Bove, Fortune, 30 Jan. 2026

Many people envision salary discussions as adversarial encounters with winners and losers. —Kwame Christian Esq, Forbes.com, 29 Jan. 2026

For one, adversarial attacks designed to mislead AI models can be used by malicious actors to misclassify data. —Connie Etemadi, Miami Herald, 28 Jan. 2026

Left to its own, Greenland will face relentless pressure from adversarial powers seeking influence through investment, infrastructure and political leverage. —Paul McCarthy, Boston Herald, 23 Jan. 2026

Word History

Etymology

adversary entry 1 + -al entry 1

First Known Use

1839, in the meaning defined above

Rhymes for adversarial

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

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