"the slayer of the bull in a bull-fight," 1670s, from Spanish matador, literally "killer," from matar "to kill," which is of uncertain origin. Probably from Latin mactare "to kill," originally "to honor by sacrifice," but this presents phonetic difficulties: "the regular evolution of this Latin base would have yielded *meitar in Portuguese and *mechar in Spanish" [Eva Núñez Méndez, "Diachronic Applications in Hispanic Linguistics"]. The alternative might be Arabic mata "he died," from Persian (see second element in checkmate). Fem. form is matadora.