noun, plural ad·ver·sar·ies.
- a person, group, or force that opposes or attacks; opponent; enemy; foe.
- a person, group, etc., that is an opponent in a contest; contestant.
- the Adversary, the devil; Satan.
adjective Also especially British, ad·ver·sar·i·al [ad-ver-sair-ee-uhl] /ˌæd vərˈsɛər i əl/.
- of or relating to an adversary.
- involving adversaries, as plaintiff and defendant in a legal proceeding: an adversary trial.
noun plural -saries
- a person or group that is hostile to someone; enemy
- an opposing contestant in a game or sport
- the US term for adversarial (def. 2)
n.mid-14c., aduersere, from Anglo-French adverser (13c.), Old French adversaire “adversary, opponent, enemy,” or directly from Latin adversarius “opponent, adversary, rival,” noun use of adjective meaning “opposite, hostile, contrary,” literally “turned toward one,” from adversus “turned against” (see adverse). The Latin word is glossed in Old English by wiðerbroca.