champion _noun

ADJECTIVES & NOUNS

world, European, national 
・At 22, he was the youngest world champion in the history of the game.

Olympic
・She’s a top international athlete and an Olympic champion.

defending, reigning
・He defeated the defending champion in the National Grand Prix.

former
・He is a former world heavyweight champion.

great
・Like all great champions, he is dedicated to his sport.

worthy
・The Australians played well and are worthy champions.

two-time, three-time, etc. 
・The five-time Wimbledon champion was beaten yesterday in a thrilling match.

junior 
・The cycling team includes the British junior champion, Andrew Wright.

boxing, tennis, golf, etc.
・He became the world boxing champion at the age of 22.

100, 200, etc. metres 
・She is the world 100 metres champion.

heavyweight, middleweight, featherweight, etc. 
・Graham’s reign as middleweight champion ended last night.

CHAMPION + NOUN
swimmer, boxer, cyclist, etc.
・Dan had been a champion swimmer in high school.

VERBS

become
・It took him only three years to become champion.

be crowned
・The next year, the team were crowned rugby champions of the world.

PHRASES

a champion defends his/her title
・He saw the world heavyweight champion Jack Dempsey defend his title against Gene Tunney.