challenger(n = noun.person) competition, competitor, contender, rival - the contestant you hope to defeat; "he had respect for his rivals"; "he wanted to know what the competition was doing"
is a kind of contestant
has particulars: champ, champion, title-holder, comer, finalist, enemy, foe, favorite, favourite, front-runner, king, queen, world-beater, runner-up, second best, scratch, semifinalist, street fighter, tier, tilter
Derived form verb challenge2
One who challenges. [1913 Webster]