9
flinty(adjective, strong, hard, tough, severe)
9
implacable(adjective, mean, strong, hard, tough)
9
indomitable(adjective, strong, hard, tough, determined)
9
stony(adjective, hard, solid, cold, indifferent)
9
unqualified(adjective, complete, total, solid, certain)
9
unshaken(adjective, set, clear, solid, cold)
8
anchored(adjective, calm, strong, secure, solid)
8
compressed(adjective, set, hard, solid, heavy)
8
concentrated(adjective, set, strong, hard, solid)
8
condensed(adjective, set, hard, solid, heavy)
8
fastened(adjective, strong, sound, secure, short)
8
flat(adjective, change, certain, definite, resolved)
8
hardy(noun, adjective, strong, sound, tough)
8
heavy(adjective, set, strong, hard, sound)
8
indefatigable(adjective, strong, tough, fit, solid)
8
purposeful(adjective, strong, tough, determined, serious)
8
rugged(adjective, set, strong, hard, sound)
8
specific(adjective, clear, certain, definite, sure)
8
strong-minded(adjective, certain, determined, significant, resolution)
8
unswayable(adjective, determined, resolute, rigid, obstinate)
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APASmart Define. (2016). firm thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/firm/thesaurus/synonyms
ChicagoSmart Define. 2016. "firm thesaurus" https://smartdefine.org/firm/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, firm thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/firm/thesaurus/synonyms>.
MLASmart Define. "firm thesaurus" 31 March 2016. Web. 22 September 2026. <https://smartdefine.org/firm/thesaurus/synonyms>