champion champion /ˈtʃæmpiːən/

adjective

1. Holding first place in a contest  ( champion , prizewinning )
   holding first place in a contest
    A champion show dog
   a champion show dog
    A prizewinning wine
   a prizewinning wine
   

noun

1. () Someone who has won first place in a competition  ( champ [Informal] , title-holder , champion )
   someone who has won first place in a competition
     The young gymnast won a gold medal and became the champion of her category.
   The young gymnast won a gold medal and became the champion of her category.
   
2. () Someone who fights for a cause  ( paladin [Archaic] , champion , fighter , hero )
   someone who fights for a cause
   
3. Someone who is dazzlingly skilled in any field  ( adept , champion , maven [Informal, American] , genius , mavin [Informal, American] , superstar , whizz [Informal] , wiz [Informal] , megastar [Informal] , ace [Informal] , hotshot [Informal] , sensation , star , virtuoso , whiz [Informal] , wizard [Informal] )
   someone who is dazzlingly skilled in any field
     The talented star dazzled audiences with her captivating performances on the stage.
   The talented star dazzled audiences with her captivating performances on the stage.
   
4. A person who backs a politician or a team etc.  ( booster , champion , friend , admirer , protagonist , supporter )
   a person who backs a politician or a team etc.
    All their supporters came out for the game
   all their supporters came out for the game
    They are friends of the library
   they are friends of the library
   

verb

1. () Protect or fight for as a champion  ( champion , defend )
   protect or fight for as a champion