adversarial

adjective

ad·​ver·​sar·​i·​al ˌad-vər-ˈser-ē-əl How to pronounce adversarial (audio)
ˌad-və-, 
-ˈse-rē-
Synonyms of adversarial
: 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

Relevance
See All Synonyms & Antonyms in Thesaurus

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
While adversarial crowds often are a home-field advantage, Matthews understands the challenge that lies ahead but is excited to be back and playing in front of the Cal faithful. — Connor Dullinger, Los Angeles Times, 30 Aug. 2026 The approach uses adversarial inverse reinforcement learning (AIRL) to learn walking strategies from stick insects. — Jijo Malayil, Interesting Engineering, 28 Aug. 2026 Ironically, Weckert used AI to design the pattern, using a kind of trial and error called an adversarial loop. — Joe Wilkins, Futurism, 26 Aug. 2026 Organizations must extend hygiene to AI systems by securing training data, confirming model integrity, safeguarding prompts and outputs, preventing model poisoning and adversarial attacks, and controlling how AI accesses company data. — Chuck Brooks, Forbes.com, 22 Aug. 2026 See All Example Sentences for adversarial

Word History

Etymology

adversary entry 1 + -al entry 1

First Known Use

1839, in the meaning defined above

Time Traveler
The first known use of adversarial was in 1839

Rhymes for adversarial

See All Rhymes for adversarial

Browse Nearby Words

adversaria
adversarial
adversary
See all Nearby Words

Cite this Entry

“Adversarial.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/adversarial. Accessed 3 Sep. 2026.

Copy Citation

Kids Definition

adversarial

adjective
ad·​ver·​sar·​i·​al ˌad-vər-ˈser-ē-əl How to pronounce adversarial (audio)
: involving two people or two sides who oppose each other

Legal Definition

adversarial

adjective
ad·​ver·​sar·​i·​al ˌad-vər-ˈser-ē-əl How to pronounce adversarial (audio)
: of, relating to, or characteristic of an adversary or adversary procedures : adversary
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

A List of Most Commonly Confused Words

Why do we use apostrophes to show possession?

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?
See More

Popular in Wordplay

See More

The Longest Long Words List

Stay Woke

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

Even More Bird Names that Sound Like Insults (and Sometimes Are)
See More

Popular

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

The Longest Long Words List

Stay Woke
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
skateboard-dog-hat
Wordmaxxing Slang Quiz Give your vocabulary a glow up by getting sendy w...
See All