4
sharply(adverb, fast, sprightly, severely, seriously)
4
strongly(adverb, fast, sprightly, severely, seriously)
4
viciously(adverb, fast, sprightly, severely, intensely)
3
hard(adjective, adverb, strong, fast, intensely)
3
brutishly(adverb, terrible, in awful way)
3
cold-fistedly(adverb, terrible, in awful way)
3
demoniacally(adverb, terrible, in awful way)
3
diabolically(adverb, terrible, in awful way)
3
energetically(adjective, adverb, fast, intensely, earnestly)
3
like mad(expression, adjective, intensely, wildly, ludicrously)
3
passionately(adverb, intensely, violently, strongly, hastily)
3
relentlessly(adverb, fast, sprightly, severely, seriously)
3
severely(adverb, fast, badly, sprightly, intensely)
3
truculently
3
turbulently(adjective, adverb, fast, sprightly, severely)
3
vengeance
3
vigorously(adverb, fast, seriously, intensely, earnestly)
2
In a cruelhearted way(adverb, terrible, in awful way)
2
actively(adverb, fast, sprightly, severely, seriously)
2
boisterously(adverb, fast, sprightly, severely, seriously)
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APASmart Define. (2016). fiercely thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/fiercely/thesaurus/synonyms
ChicagoSmart Define. 2016. "fiercely thesaurus" https://smartdefine.org/fiercely/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2016, fiercely thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/fiercely/thesaurus/synonyms>.
MLASmart Define. "fiercely thesaurus" 24 March 2016. Web. 21 September 2026. <https://smartdefine.org/fiercely/thesaurus/synonyms>