134 entries under firm topic. ×

13
fixed(adjective, strong, sound, secure, tough)
13
resolved(adjective, strong, flat, determined)
13
strong(adjective, sound, secure, tough, fit)
12
intransigent(adjective, strong, determined, unreasonable)
12
tireless(adjective, strong, determined, steady)
11
refractory(adjective, tough, difficult, wild)
11
stalwart(adjective, strong, sound, tough, fit)
11
strong-willed(adjective, strong, intense, deliberate)
11
unflagging(adjective, strong, tough, fit)
10
clinging(adjective, strong, free, resolute)
10
headstrong(adjective, tough, resist, awkward)
10
immovable(adjective, strong, secure, solid)
10
indomitable(adjective, strong, tough, difficult)
10
purposeful(adjective, strong, determined, serious)
10
sturdy(adjective, strong, sound, tough, fit)
10
unflinching(adjective, strong, flat, determined)
9
fast(adjective, strong, free, secure, tough)
9
inexorable(adjective, tough, determined, resolute)
9
pigheaded(adjective, tough, difficult, resist)
9
unswerving(adjective, strong, determined, steady)
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APASmart Define. (2015). tenacious thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/tenacious/thesaurus/synonyms
ChicagoSmart Define. 2015. "tenacious thesaurus" https://smartdefine.org/tenacious/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, tenacious thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/tenacious/thesaurus/synonyms>.
MLASmart Define. "tenacious thesaurus" 6 November 2015. Web. 24 September 2026. <https://smartdefine.org/tenacious/thesaurus/synonyms>