5
unconquerable(adjective, obstinate, insistent, dogged)
4
bound and determined(expression, adjective, idiom, determined, serious)
4
committed(adjective, resolute, dedicated, unwavering, unfaltering)
4
conscientious
4
contrary(adjective, determined, fixed, obstinate, stubborn)
4
dependable(adjective, strong, tough, certain, regular)
4
energetic
4
evergreen
4
flat(adjective, strong, certain, definite, continuous)
4
froward(adjective, deliberate, determined, obstinate, insistent)
4
game(adjective, determined, resolute, brave, willing)
4
hardy(tough, determined, resolute, sturdy, hard-wearing)
4
homogeneous(adjective, regular, even, constant, uniform)
4
intrepid
4
invincible(adjective, obstinate, insistent, dogged)
4
laborious
4
level(adjective, continuous)
4
lifelong(adjective, continuous, hardened, lasting, continuing)
4
monolithic(adjective, continuous)
4
nagging
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APASmart Define. (2015). persistent thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/persistent/thesaurus/synonyms
ChicagoSmart Define. 2015. "persistent thesaurus" https://smartdefine.org/persistent/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, persistent thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/persistent/thesaurus/synonyms>.
MLASmart Define. "persistent thesaurus" 1 June 2015. Web. 20 September 2026. <https://smartdefine.org/persistent/thesaurus/synonyms>