ferociously, savagely, passionately, furiously, viciously, tigerishly
she fiercely ran from the dog....
Fierce and fiercely are adjectives. There is no noun related to "fiercely".
The neighbors had bought a new watchdog, and he grimaced fiercely as I walked by.
The correct spelling is "fiercely."
Fiercely is an adverb.
Fiercely is an adverb (ferociously, violently). The adjective is simply fierce.
comparative=fiercer superlative=fiercest
The Battle of The Alamo was fiercely fought by it's defenders, but they ultimately lost. My heart just stopped when the big grizzly bear fiercely bared her teeth.
The word glare means to stare fiercely. One will often say someone glared at them, meaning they gave them a harsh or bad look. Some synonyms for glare are stare, look and gaze.
No, it is not a verb. Fiercely is an adverb.
Firecely make a sentence
fiercely