Deadhead (n.)youdaoicibaDictYouDict[Deadhead 词源字典]
by 1974 in sense of "devotee of the rock music band the Grateful Dead;" earlier (with lower-case) "one who rides for free on the railroads" (1866), and "non-paying spectator" (1841).[Deadhead etymology, Deadhead origin, 英语词源]