1. untamed; cruel, fell, brutal; barbarous, bloodthirsty, murderous. Fierce, ferocious, truculent suggest vehemence and violence of temper, manner, or action: fierce in repelling a foe. Ferocious implies fierceness or cruelty, especially of a bloodthirsty kind, in disposition or action: a ferocious glare; ferocious brutality toward helpless refugees. Truculent suggests an intimidating or bullying fierceness of manner or conduct: His truculent attitude kept them terrified and submissive. 2, 3. furious, passionate, turbulent.