say it: FIR-slee
fiercely is an adverb meaning "in a physically fierce manner". It carries 2 recorded senses.
in a physically fierce manner
“silence broken by dogs barking ferociously”
“they fought fiercely”
in an emotionally fierce manner
“she was fiercely proud of her children”
Definitions, synonyms and semantic relations for fiercely come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.