champion

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One that wins first place or first prize in a competition.
• noun One that is clearly superior or has the attributes of a winner.
• noun An ardent defender or supporter of a cause or another person.
• noun One who fights; a warrior.
• transitive verb To fight for, defend, or support as a champion: synonym: support.
• transitive verb Obsolete To defy or challenge.
• adjective Holding first place or prize.
• adjective Superior to all others.

from The Century Dictionary.

• To maintain or support by contest or advocacy; act as champion for.
• See champian.
• noun One who undertakes to defend any cause; especially, one who engages in combat or contention in behalf of another, or in any representative capacity: as, the champion of an army or of a party; a champion for the truth, or of innocence.
• noun More generally, a hero; a brave warrior.
• noun One who has demonstrated his superiority to all others in some matter decided by public, contest or competition, as prize-fighting, pedestrianism, rowing, plowing, etc.
• First among all competitors or contestants: as, a champion oarsman.
• Hence By extension, of the first rank or highest excellence in any respect; unexcelled.
• noun An animal or a plant to which, or to its owner, the first prize has been awarded in any general competition, as at a horse-, cattle-, bench-, or other show, or which has taken a number of prizes.
• noun Some variety of vegetable, fruit, implement, or the like, for which the highest excellence is claimed.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To furnish with a champion; to attend or defend as champion; to support or maintain; to protect.
• noun One who engages in any contest; especially one who in ancient times contended in single combat in behalf of another's honor or rights; or one who now acts or speaks in behalf of a person or a cause; a defender; an advocate; a hero.
• noun One who by defeating all rivals, has obtained an acknowledged supremacy in any branch of athletics or game of skill, and is ready to contend with any rival.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Someone who has been a winner in a contest.
• noun Someone who is chosen to represent a group of people in a contest.
• adjective attributive Acting as a champion; that has defeated all one's competitors.
• adjective attributive Excellent; beyond compare.
• adjective (Ireland, colloquial) Excellent; superb; deserving of high praise.
• verb to promote, advocate, or act as a champion for

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone who has won first place in a competition
• noun someone who is dazzlingly skilled in any field
• noun someone who fights for a cause
• verb protect or fight for as a champion
• noun a person who backs a politician or a team etc.
• adjective holding first place in a contest