211 entries under severe topic. ×

16
ruthless(adjective, animal, appearance, mean, hard)
16
unforgiving(adjective, mean, hard, tough)
14
severe(adjective, appearance, mean, strong, hard)
14
hard-nosed(adjective, mean, strong, hard, tough)
14
merciless(adjective, appearance, mean, hard, tough)
13
hard(adjective, mean, strong, tough)
13
pitiless(adjective, animal, mean, hard, tough)
13
unappeasable(adjective, mean, harsh, cruel)
11
savage(adjective, animal, mean, strong, hard)
11
strict(adjective, strong, hard, tough)
11
unflinching(adjective, mean, firm, harsh)
10
austere(adjective, appearance, mean, strong, hard)
10
exacting(adjective, persistent, severity, obstinate)
10
fierce(adjective, animal, mean, hard, tough)
10
stiff-necked(adjective, mean, strong, hard, tough)
10
tough(adjective, mean, strong, hard)
10
unmerciful(adjective, mean, hard, tough)
9
rigorous(adjective, strong, hard, tough)
8
brutal(adjective, mean, strong, evil)
8
callous(adjective, mean, hard, evil)
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APASmart Define. (2015). relentless thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/relentless/thesaurus/synonyms
ChicagoSmart Define. 2015. "relentless thesaurus" https://smartdefine.org/relentless/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, relentless thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/relentless/thesaurus/synonyms>.
MLASmart Define. "relentless thesaurus" 24 June 2015. Web. 24 September 2026. <https://smartdefine.org/relentless/thesaurus/synonyms>