adj. fierc·er, fierc·est
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.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.