vehemence vs fierceness

vehemence and fierceness both are nouns.

Word	Noun	Adjective	Verb	Adverb
vehemence	Yes	No	No	No
fierceness	Yes	No	No	No

As nouns, vehemence and fierceness are synonyms defined as:

Other synonyms of vehemence include ferocity, furiousness, fury, violence, wildness.

vehemence (noun)	fierceness (noun)
the property of being wild or turbulent	the property of being wild or turbulent
intensity or forcefulness of expression