fierce

Synonyms: angry animal ape awful barbarous bloodthirsty blustery boisterous bold brutal brutish cruel cutthroat dangerous enraged fell feral ferocious fiery flipped frightening furious horrible howling impetuous infuriated intense malevolent malign murderous passionate powerful primitive raging raving relentless savage stormy strong tempestuous terrible threatening tigerish truculent tumultous/tumultuous uncontrollable untamed vehement venomous vicious wild

Antonyms: calm gentle kind meek nonviolent peaceful tame tender unthreatening