Learner's definition of FIERCE
1 a : very violent b : eager to fight or kill
a fierce tiger/warrior
a fierce fighter
2 : having or showing a lot of strong emotion: very strong or intense
a fierce argument/struggle
The proposal has faced fierce opposition.
The two teams have had a fierce rivalry for many years.
He's admired for his fierce independence.
She's a fierce competitor.
You could see the fierce determination in her eyes.
3 : very harsh or powerful
something fierceUS, informal
: very badly or very much
— fiercelyadverb,[more fiercely; most fiercely]