■ noun
1》 a person who has surpassed all rivals in a sporting contest or other competition.
2》 a defender of a cause or person.
↘ historical a knight who fought in single combat on behalf of the monarch.
■ verb support the cause of.
■ adjective Brit. informal or dialect excellent.
Origin
ME: from OFr., from med. L. campio(n-) 'fighter', from L. campus (see camp 1 ).