Meaning

• An ongoing winner in a game or contest.

  "The defending champion is expected to defeat his challenger."

• Someone who is chosen to represent a group of people in a contest.

  "Barcelona is eligible to play in FIFA Club World Cup as the champion of Europe."

• Someone who fights for a cause or status.

  "champion of women's suffrage"

• Someone who fights on another's behalf.

  "champion of the poor"

Meaning

• To promote, advocate, or act as a champion for (a cause, etc.).

• To challenge.

Meaning

• Acting as a champion; that has defeated all one's competitors.

• Excellent; beyond compare.

• (predicative) Excellent; brilliant; superb; deserving of high praise.

  ""That rollercoaster was champion," laughed Vinny."