truculent

Synonyms: abusive aggressive antagonistic bad-tempered barbarous bellicose browbeating brutal bullying caustic combative contentious contumelious cowing cross defiant ferocious fierce frightening harsh hostile inhuman inhumane intimidating invective mean militant mordacious mordant obstreperous opprobrious ornery pugnacious quarrelsome rude savage scathing scrappy scurrilous sharp sullen terrifying terrorizing trenchant violent vituperative vituperous

Antonyms: cooperative gentle mild nice tame