142 entries under grim topic. ×

11
merciless(adjective, hard, severe, rough, harsh)
11
relentless(adjective, mean, strong, hard, severe)
11
rigorous(adjective, strong, hard, severe, rough)
10
unrelenting(adjective, mean, strong, hard, severe)
9
intractable(adjective, hard, rough, firm, difficult)
9
stringent(adjective, hard, severe, firm, difficult)
8
austere(adjective, strong, hard, severe, sharp)
8
hard-hearted(adjective, mean, hard, severe, harsh)
8
persistent(adjective, firm, unreasonable, resolute)
8
pitiless(adjective, hard, severe, sharp, harsh)
8
thick-skinned(noun, adjective, mean, hard, severe)
8
tiring(adjective, dull, difficult, boring)
8
unsparing(adjective, strong, hard, severe, rough)
7
inexorable(adjective, mean, strong, hard, firm)
7
tyrannical(adjective, hard, harsh, cruel)
7
wearisome(adjective, dull, severe, difficult, boring)
6
cold-blooded(adjective, calm, mean, hard, cool)
6
headstrong(adjective, hard, rough, firm, difficult)
6
implacable(adjective, mean, strong, hard, firm)
6
inhuman(adjective, hard, severe, harsh, violent)
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APASmart Define. (2016). tough thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/tough/thesaurus/synonyms
ChicagoSmart Define. 2016. "tough thesaurus" https://smartdefine.org/tough/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2016, tough thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/tough/thesaurus/synonyms>.
MLASmart Define. "tough thesaurus" 30 March 2016. Web. 28 September 2026. <https://smartdefine.org/tough/thesaurus/synonyms>