From Latinferox (“wild, bold, savage, fierce”), from ferus (“wild, savage, fierce”).
From Latin ferōxferōc-fierceghwer- in Indo-European roots
American Heritage Dictionary of the English Language, 5th Edition
Ferocious Sentence Examples
The stories of his ferocious savagery exceed belief.
After a ferocious contest, the Danes were practically annihilated.
They fought with the grey swords, combining the sword dance with hand-to-hand combat moves for a ferocious battle that surprised her.
In the early part of his reign he appears, in agreement with the Turkish sultan and the king of Poland, turning out the Hungarian vassal, the ferocious Vlad, from the Walachian throne, and annexing the coast cities of Kilia and Cetatea Alba or Byelgorod, the Turkish Akkerman.
For ferocious cats, you can find panthers, tigers, lions, and wildcats.