fierce vs vehement

fierce and vehement both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fierce	No	Yes	No	No
vehement	No	Yes	No	No

As adjectives, fierce and vehement are synonyms defined as:

fierce and vehement: marked by extreme intensity of emotions or convictions; inclined to react violently; fervid

Other synonyms of fierce include tearing, trigger-happy, violent.

fierce (adjective)	vehement (adjective)
marked by extreme intensity of emotions or convictions; inclined to react violently; fervid	marked by extreme intensity of emotions or convictions; inclined to react violently; fervid
ruthless in competition	characterized by great force or energy
violently agitated and turbulent
marked by extreme and violent energy