1 vehemently aggressive or frightening in temper or action, violent.
2 eager, intense, ardent.
3 unpleasantly strong or intense; uncontrolled (fierce heat).
4 (of a mechanism) not smooth or easy in action.
Derivatives:
fiercely adv. fierceness n.
Etymology: ME f. AF fers, OF fiers fier proud f. L ferus savage
Useful english dictionary. 2012.