opponent
noun
əˈpəʊnənt 
əˈpoʊnənt 
1 a person that you are playing or fighting against in a game, competition, argument, etc.Synonym
adversarya political opponenta dangerous/worthy/formidable opponentThe team's opponents are unbeaten so far this season.2 opponent (of something) a person who is against something and tries to change or stop itopponents of abortionopponents of the regime