fe·ro·cious 
(fə-rōshəs)
(fə-rōshəs)adj.
1.
a. Extremely aggressive or violent: a ferocious attack dog.
b. Characterized by or showing extreme aggressiveness or violence: a ferocious glare; ferocious claws.
2. Extremely powerful or destructive: a ferocious gale.
3. Extreme in activity or feeling; intense: a ferocious demand for a product; ferocious courage.
[From Latin ferōx, ferōc-, fierce; see ghwer- in the Appendix of Indo-European roots.]
fe·rocious·ly adv.
fe·roci·ty (-rŏsĭ-tē), fe·rocious·ness n.