Merriam-Webster's Collegiate® Dictionary, 11th Edition
CHAMPION
I. noun
Etymology: Middle English, from Anglo-French, from Medieval Latin campion-, campio, of West Germanic origin; akin to Old English cempa warrior
Date: 13th century
warrior , fighter , a militant advocate or defender , one that does battle for another's rights or honor , a winner of first prize or first place in competition,
II. transitive verb
Date: 1605
challenge , defy , to protect or fight for as a champion, to act as militant supporter of ; uphold , advocate , see: support