88 entries under firm topic. ×

5
mulish(adjective, mean, strong, hard, tough)
5
sturdy(adjective, strong, hard, tough, continue)
5
unshaken(adjective, clear, strong, solid)
4
sound(adjective, strong, hard, secure, continue)
4
tough(adjective, mean, strong, hard)
3
unchanging(adjective, clear, solid, certain)
2
balky(tough, unreasonable, grim, inflexible)
2
bold(adjective, determined, resolute, confident)
2
certain(adjective, clear, complete, definite)
2
decided(adjective, clear, certain, definite)
2
definite(adjective, clear, strong, complete)
2
hardheaded(tough, determined, resolute, obstinate)
2
persevering(adjective, strong, tough, determined)
2
refractory(adjective, tough, unreasonable, grim)
2
settled(strong, secure, substantial, stable)
2
single-minded(adjective, tough, solid, determined)
2
tight(adjective, strong, hard, secure, tough)
2
undaunted(adjective, determined, bold, resolute)
2
unhesitating(adjective, complete, certain, obedient)
1
accurate(complete, certain, established, obedient)
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APASmart Define. (2015). unshakable thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/unshakable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unshakable thesaurus" https://smartdefine.org/unshakable/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2015, unshakable thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/unshakable/thesaurus/synonyms>.
MLASmart Define. "unshakable thesaurus" 10 April 2015. Web. 28 September 2026. <https://smartdefine.org/unshakable/thesaurus/synonyms>