opponent
I
noun
adversarius, adversary, adverse party, challenger, combatant, contender, cornval, disputant, one who opposes, opposer, opposing litigant, opposing party, opposite, opposite side, opposition, other side
II
index
adversary, contender, contestant, contradictory, disputant, foe, litigant, plaintiff, rival
Burton's Legal Thesaurus.
William C. Burton.
2006