fierce 
(fîrs)
(fîrs)adj. fierc·er, fierc·est
1.
a. Hostile and violent, especially by nature or temperament; ferocious: The Huns were fierce warriors.
b. Characterized by or showing hostility: gave us a fierce look.
2. Extremely powerful or destructive: a fierce storm; a fierce flood.
3. Intense in activity or feeling; vigorous or ardent: a fierce debate; fierce loyalty.
[Middle English fiers, from Old French, from Latin ferus; see ghwer- in the Appendix of Indo-European roots.]
fiercely adv.
fierceness n.