Be ferocious means to be fierce, aggressive, or violent in nature. Its synonyms include savage, brutal, menacing, intimidating, fierce, ruthless, and vicious. All these words express a strong and threatening behavior. For instance, if someone is described as savage, they are seen as uncontrolled and untamed. A brutal individual does not hold back and can be merciless. Menacing implies a feeling of danger. Intimidating describes someone who is frightening and demanding. Fierce suggests that someone is bold and aggressive. Ruthless means that someone is without mercy and ready to take harsh actions. Lastly, vicious describes someone who is cruel and capable of inflicting harm. These synonyms highlights the level of edginess and intensity associated with being ferocious.