Origin and history of brut

early 15c., "of or belonging to animals, non-human," from Old French brut "coarse, brutal, raw, crude," from Latin brutus "heavy, dull, stupid, insensible, unreasonable" (source also of Spanish and Italian bruto), said to be an Oscan word, from PIE *gwruto-, suffixed form of root *gwere- (1) "heavy" (see de Vaan).

Before reaching English the meaning expanded to "of the lower animals." Used in English of human beings from 1530s, "wanting in reason, blunt or dull of sentiment, unintelligent." The sense in brute force (1736) is "irrational, purely material."

Brute ... remains nearest to the distinguishing difference between man and beast, irrationality .... Brutish is especially uncultured, stupid, groveling .... Brutal implies cruelty or lack of feeling: as brutal language or conduct. [Century Dictionary]

gwerə-, Proto-Indo-European root meaning "heavy."

It might form all or part of: aggravate; aggravation; aggrieve; bar (n.4) "unit of pressure;" bariatric; baritone; barium; barometer; blitzkrieg; brig; brigade; brigand; brigantine; brio; brut; brute; charivari; gravamen; grave (adj.); gravid; gravimeter; gravitate; gravity; grief; grieve; kriegspiel; guru; hyperbaric; isobar; quern; sitzkrieg.

It might also be the source of: Sanskrit guruh "heavy, weighty, venerable;" Greek baros "weight," barys "heavy in weight," often with the notion of "strength, force;" Latin gravis, "heavy, ponderous, burdensome, loaded; pregnant;" Old English cweorn "quern;" Gothic kaurus "heavy;" Lettish gruts "heavy."