champion

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One that wins first place or first prize in a competition.
2. n. One that is clearly superior or has the attributes of a winner: a champion at teaching.
3. n. An ardent defender or supporter of a cause or another person: a champion of the homeless.
4. n. One who fights; a warrior.
5. v. To fight for, defend, or support as a champion: championed the cause of civil rights. See Synonyms at support.
6. v. Obsolete To defy or challenge.
7. adj. Holding first place or prize: a champion show dog.
8. adj. Superior to all others: "the champion playboy of the Western World” ( John Millington Synge).

Century Dictionary and Cyclopedia

1. n. 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.
2. n. More generally, a hero; a brave warrior.
3. n. 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.
4. First among all competitors or contestants: as, a champion oarsman.
5. Hence By extension, of the first rank or highest excellence in any respect; unexcelled.
6. To maintain or support by contest or advocacy; act as champion for.
7. See champian.
8. n. 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.
9. n. Some variety of vegetable, fruit, implement, or the like, for which the highest excellence is claimed.

Wiktionary

1. n. Someone who has been a winner in a contest.
2. n. Someone who is chosen to represent a group of people in a contest.
3. adj. attributive Acting as a champion; that has defeated all one's competitors.
4. adj. attributive Excellent; beyond compare.
5. adj. (Ireland, colloquial) Excellent; superb; deserving of high praise.
6. v. to promote, advocate, or act as a champion for

GNU Webster's 1913

1. n. 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.
2. n. 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.
3. v. To furnish with a champion; to attend or defend as champion; to support or maintain; to protect.

WordNet 3.0

1. n. someone who has won first place in a competition
2. n. someone who is dazzlingly skilled in any field
3. n. someone who fights for a cause
4. v. protect or fight for as a champion
5. n. a person who backs a politician or a team etc.
6. adj. holding first place in a contest