Emily Dickinson Lexicon

OP-POS-ER, n.

1. One that opposes; an opponent in party, in principle, in controversy or argument. We speak of the opposers of public measures; the opposers of ecclesiastical discipline; an opposer of Christianity or of orthodoxy.
2. One who acts in opposition; one who resists; as, an opposer of law or of the execution of law.
3. An antagonist; an adversary; an enemy; a rival.