134 entries under firm topic. ×

6
undaunted(adjective, strong, tough, steady)
5
balky(tough, unreasonable, grim, inflexible)
5
bound(adjective, strong, flat, solid)
5
dedicated(adjective, clear, strong, tough, severe)
5
iron(adjective, strong, tough, solid)
5
lasting(adjective, tough, true, fixed)
5
loyal(adjective, true, fixed, resolute)
5
opinionated(tough, unreasonable, grim, persistent)
5
patient(adjective, strong, determined, steady)
5
recalcitrant(adjective, tough, difficult, wild)
5
stable(adjective, strong, sound, secure, tough)
5
unfailing(adjective, strong, determined, steady)
5
willful(adjective, tough, difficult, resist)
4
adherent(true, fixed, constant, tacky)
4
contumacious(adjective, tough, persistent, obstinate)
4
powerful(adjective, strong, sound, tough, fit)
4
self-willed(adjective, tough, difficult, wild)
4
serious(adjective, strong, determined, resolute)
4
solid(adjective, strong, sound, secure, tough)
4
substantial(adjective, strong, sound, tough, fit)
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APASmart Define. (2015). tenacious thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/tenacious/thesaurus/synonyms
ChicagoSmart Define. 2015. "tenacious thesaurus" https://smartdefine.org/tenacious/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, tenacious thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/tenacious/thesaurus/synonyms>.
MLASmart Define. "tenacious thesaurus" 6 November 2015. Web. 25 September 2026. <https://smartdefine.org/tenacious/thesaurus/synonyms>