1 set oneself against; resist, argue against.
2 be hostile to.
3 take part in a game, sport, etc., against (another competitor or team).
4 (foll. by to) place in opposition or contrast.
Phrases and idioms:
as opposed to in contrast with.
Derivatives:
opposer n.
Etymology: ME f. OF opposer f. L opponere: see OPPONENT
Useful english dictionary. 2012.