124 entries under hard topic. ×

4
conclusive(adjective, clear, sound, complete)
4
sound(adjective, clear, strong, secure)
4
stony(adjective, firm, solid, stiff)
4
strict(adjective, strong, severe, stiff)
3
concrete(adjective, set, strong, solid)
3
congealed(verb, adjective, set, firm)
3
dyed-in-the-wool(adjective, set, rigid, strict)
3
pigheaded(adjective, mean, tough, firm)
3
refractory(adjective, tough, rough, firm)
3
rigorous(adjective, severe, stiff, rigid)
3
steely(adjective, firm, solid, rigid)
3
sturdy(adjective, close, strong, sound)
3
thick(adjective, strong, firm, solid)
3
unadaptable(adjective, set, stiff, rigid)
2
contracted(verb, adjective, slight, fine)
2
hardened(adjective, set, complete, firm)
2
harsh(adjective, mean, severe, rough)
2
implacable(adjective, mean, tough, firm)
2
incompliant(adjective, firm, solid, stiff)
2
ironclad(adjective, set, firm, determined)
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APASmart Define. (2016). fixed thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/fixed/thesaurus/synonyms
ChicagoSmart Define. 2016. "fixed thesaurus" https://smartdefine.org/fixed/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, fixed thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/fixed/thesaurus/synonyms>.
MLASmart Define. "fixed thesaurus" 16 March 2016. Web. 22 September 2026. <https://smartdefine.org/fixed/thesaurus/synonyms>