Answer: opposer

AnswerCrossword Clue
OPPOSERAnti
OPPOSEROne against
OPPOSERAnti.
OPPOSERCombatant.
OPPOSER"No" voter
OPPOSEREnemy
OPPOSERSupporter's foe
opposerone that opposes (to conflict with)
opposerto resist
opposerto set (something) opposite something else
opposerto be hostile to