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From Middle English champioun, from Old French champion, from Medieval Latin campio (“combatant in a duel, champion”), from Frankish *kampijō (“fighter”), from Proto-West Germanic *kampijō (“combat soldier”), a derivative of Proto-West Germanic *kampijan (“to battle, to campaign”), itself a derivative of Proto-West Germanic *kamp (“battlefield, battle”), ultimately a borrowing in Proto-West-Germanic from Latin campus (“a field, a plain, a place of action”).

champion (plural champions)

champion of the poor

The defending champion is expected to defeat his challenger.

someone who has been winner in a contest