deu·ter·ag·o·nist \ˌd(y)üd.əˈragənə̇st, -raig-\noun (-s) Etymology: Greek deuteragōnistēs, from deuter- deuter- (I) + agōnistēs combatant, actor — more at agonist 1.: the actor taking the part of second importance in a classical Greek drama 2.: a person who serves as a foil to another