challenger (n.)youdaoicibaDictYouDict[challenger 词源字典]
late 13c., "a claimant;" mid-14c., "one who makes false charges;" mid-15c., "one who disputes something, objector," from Anglo-French chalengeour (Old French chalongeor "slanderer, petitioner, plaintiff"), agent noun from challenge (v.). Specific sense of "one who calls out another in a contest" is from 1510s.[challenger etymology, challenger origin, 英语词源]