From The Collaborative International Dictionary of English v.0.48 [gcide]:
Fierce \Fierce\, a. [Compar. Fiercer; superl. Fiercest.]
[OE. fers, fiers, OF. fier, nom. fiers, fierce, savage,
cruel, F. fier proud, from L. ferus wild, savage, cruel;
perh. akin to E. bear the animal. Cf. Feral, Ferocity.]
1. Furious; violent; unrestrained; impetuous; as, a fierce
wind.
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His fierce thunder drove us to the deep. --Milton.
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2. Vehement in anger or cruelty; ready or eager to kill or
injure; of a nature to inspire terror; ferocious. "A
fierce whisper." --Dickens. "A fierce tyrant." --Pope.
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The fierce foe hung upon our broken rear. --Milton.
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Thou huntest me as a fierce lion. --Job. x. 16.
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3. Excessively earnest, eager, or ardent.
Syn: Ferocious; savage; cruel; vehement; impetuous;
barbarous; fell. See Ferocious. -- Fierce"ly, adv.
-- Fierce"ness, n.
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From WordNet (r) 3.0 (2006) [wn]:
fierce
adj 1: marked by extreme and violent energy; "a ferocious
beating"; "fierce fighting"; "a furious battle" [syn:
ferocious, fierce, furious, savage]
2: marked by extreme intensity of emotions or convictions;
inclined to react violently; fervid; "fierce loyalty"; "in a
tearing rage"; "vehement dislike"; "violent passions" [syn:
fierce, tearing, vehement, violent, trigger-happy]
3: ruthless in competition; "cutthroat competition"; "bowelless
readiness to take advantage" [syn: cutthroat, fierce,
bowelless]
4: violently agitated and turbulent; "boisterous winds and
waves"; "the fierce thunders roar me their music"- Ezra
Pound; "rough weather"; "rough seas" [syn: boisterous,
fierce, rough]