150 entries under grim topic. ×

6
rigorous(adjective, strong, hard, tough, severe)
6
strict(adjective, strong, hard, tough, severe)
6
unsympathetic(adjective, animal, mean, hard, tough)
5
bullheaded(adjective, strong, hard, tough, firm)
5
perverse(adjective, mean, hard, tough, harsh)
4
barbarous(adjective, animal, appearance, mean, hard)
4
bitter(adjective, strong, hard, tough, severe)
4
brutal(adjective, mean, hard, tough, severe)
4
callous(adjective, mean, hard, tough, severe)
4
dour(adjective, close, hard, tough, severe)
4
exacting(adjective, tough, severe, harsh, cruel)
4
hard-hearted(adjective, mean, hard, tough, evil)
4
unfeeling(adjective, animal, mean, hard, tough)
4
unsparing(adjective, mean, strong, hard, tough)
3
fierce(adjective, animal, mean, hard, tough)
3
forbidding(adjective, close, appearance, strong, hard)
3
inclement(adjective, tough, harsh, cruel)
3
single-minded(adjective, tough, firm, harsh, cruel)
2
astringent(adjective, strong, hard, tough, severe)
2
authoritarian(adjective, strong, hard, tough, severe)
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APASmart Define. (2015). unrelenting thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/unrelenting/thesaurus/synonyms
ChicagoSmart Define. 2015. "unrelenting thesaurus" https://smartdefine.org/unrelenting/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2015, unrelenting thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/unrelenting/thesaurus/synonyms>.
MLASmart Define. "unrelenting thesaurus" 3 August 2015. Web. 28 September 2026. <https://smartdefine.org/unrelenting/thesaurus/synonyms>