280 entries under tough topic. ×

21
grim(adjective, person, mean, strong)
21
stony(adjective, mean, cool, severe)
20
merciless(adjective, mean, severe, evil)
20
strict(adjective, strong, easy, severe)
19
flinty(adjective, strong, severe, evil)
19
heartless(adjective, person, mean, feeling, cool)
19
insensitive(adjective, person, mean, cool)
19
onerous(adjective, dull, great, severe)
19
rigorous(adjective, strong, severe, rough)
18
troublesome(adjective, evil, difficulty, rough)
17
cold-blooded(adjective, person, mean, cool)
17
hardened(adjective, severe, firm, attitude)
17
ruthless(adjective, mean, severe, evil)
17
strenuous(adjective, dull, great, severe)
17
unkind(adjective, person, mean, cool)
16
exacting(adjective, dull, easy, severe)
16
obstinate(adjective, mean, rough, harsh)
16
unbending(adjective, mean, strong, severe)
16
unrelenting(adjective, mean, strong, severe)
15
impenetrable(adjective, characteristic, firm, solid)
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APASmart Define. (2016). hard thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/hard/thesaurus/synonyms
ChicagoSmart Define. 2016. "hard thesaurus" https://smartdefine.org/hard/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2016, hard thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/hard/thesaurus/synonyms>.
MLASmart Define. "hard thesaurus" 24 March 2016. Web. 28 September 2026. <https://smartdefine.org/hard/thesaurus/synonyms>