early 15c., "of or belonging to animals," from M.Fr. brut
"coarse, brutal, raw, crude," from L. brutus
"heavy, dull, stupid," an Oscan word, from PIE base *gwer-
"heavy" (see grave
(adj.)). Before reaching English the meaning expanded to "of the lower animals." Used of human beings from 1530s. The noun is from 1610s.