Synonyms of barbarous

1 Syllable
cruel, rough, rude, grim, wild
2 Syllables
crueler, monstrous, wilder, brutish, fiercest, brutal, wolfish, lawless, lowbrow, bestial, fiercer, cutthroat, ruthless, wicked, hellish, gothic, cruelest, coarse, wildest, uncouth, grimmer, ruder, unkind, vicious, rudest, feller, grimmest, vulgar, beastly, heartless
3 Syllables
recusant, pitiless, graceless, barbarian, barbaric, atrocious, beastlike, truculent, unplowed, unfarmed, uncivil, sadistic, coldblooded, outlandish, untilled, barbarians, ignorant, merciless, ferine, cold-blooded, ferocious, inhuman, tigerish, untamed
4 Syllables
stony-hearted, uncultured, iron-fisted, anarchistic, atavistic, remorseless, unpeaceful, stonyhearted, inhumane, inartistic, primitive, unrepenting, ironfisted, piratical
5 Syllables
unconscionable, uncivilized, preliterate, nonliterate, uncultivated
6 Syllables
unsophisticated, undomesticated