From BiblePortal Wikipedia

King James Dictionary [1]

Fierce, n. fers. L. ferus, ferox, the primary sense of which is wild, running, rushing.

1. Vehement violent furious rushing impetuous as a fierce wind. 2. Savage ravenous easily enraged as a fierce lion. 3. Vehement in rage eager of mischief as a fierce tyrant a monster fierce for blood. 4. Violent outrageous not to be restrained.

Cursed be their anger, for it was fierce.  Genesis 49 .

5. Passionate angry furious. 6. Wild staring ferocious as a fierce countenance. 7. Very eager ardent vehement as a man fierce for his party.

Webster's Dictionary [2]

(1): ( superl.) Excessively earnest, eager, or ardent.

(2): ( superl.) Vehement in anger or cruelty; ready or eager to kill or injure; of a nature to inspire terror; ferocious.

(3): ( superl.) Furious; violent; unrestrained; impetuous; as, a fierce wind.