What does "opponent" mean?

Additional senses

1. 2.One who opposes in a disputation, argument, or other verbal controversy; specifically, one who attacks some theirs or proposition, in distinction from the respondent, or defendant, who maintains it. How becomingly does Philopolis exercise his office, and seasonably commit the opponent with the respondent, like a long-practiced moderator! Dr. H. More. See Adversary.