207 entries under hard topic. ×

12
concrete(verb, adjective, close, set, clear)
12
hard-nosed(adjective, mean, clear, strong)
12
impenetrable(adjective, close, set, solid)
12
inelastic(adjective, tough, solid, determined)
12
severe(adjective, clear, strong, tough)
12
steely(adjective, strong, tough, solid)
12
stern(adjective, tough, severe, rough)
12
taut(adjective, strong, secure, rough)
12
tense(verb, adjective, strengthen, stiff)
12
thick(adjective, close, strong, tough)
11
confirmed(adjective, characteristic, rough, harsh)
10
close(adjective, set, fix, settle)
10
immutable(adjective, calm, strong, secure)
10
set in stone(expression, adjective, idiom, calm, set)
9
flinty(adjective, strong, tough, severe)
9
implacable(adjective, mean, strong, tough)
9
indomitable(adjective, strong, tough, determined)
9
stony(adjective, solid, cold, indifferent)
8
compressed(adjective, set, solid, heavy)
8
concentrated(adjective, set, strong, solid)
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APASmart Define. (2016). firm thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/firm/thesaurus/synonyms
ChicagoSmart Define. 2016. "firm thesaurus" https://smartdefine.org/firm/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, firm thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/firm/thesaurus/synonyms>.
MLASmart Define. "firm thesaurus" 31 March 2016. Web. 25 September 2026. <https://smartdefine.org/firm/thesaurus/synonyms>