Longman Dictionary of Contemporary English - champion

~1 n 1 someone or something that has won a competition, especially in sport  (the world heavyweight boxing champion | reigning champion (=the champion at the present time)) 2 champion of someone who publicly fights for and defends an aim or principle, such as the rights of a group of people  (a champion of women's rights) ~2 v to publicly fight for and defend an aim or principle, such as the rights of a group of people  (championing the cause of religious freedom)