5
unyielding(adjective, resolute)
4
abiding(adjective, persevering)
4
continuing(adjective, strong, firm, determined, steady)
4
continuous(adjective, continuous)
4
courageous(adjective, resolute, tenacious)
4
dauntless(adjective, resolute, tenacious)
4
hard(adjective, tenacious)
4
hard-working(adjective, activity)
4
intent(adjective, activity, resolute)
4
lasting(adjective, continuous, persevering)
4
persisting
4
single-minded
4
spirited(adjective, strong, moving, lively, active)
4
true(adjective, resolute, tenacious)
4
unchangeable(adjective, resolute, continuous, perseverance)
4
unrelenting
3
bulldogged(adjective, tenacious)
3
bullheaded(adjective, resolute, tenacious)
3
conscientious
3
eager
11 years ago|10k views|share |citing 
APASmart Define. (2015). indefatigable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/indefatigable/thesaurus/synonyms
ChicagoSmart Define. 2015. "indefatigable thesaurus" https://smartdefine.org/indefatigable/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2015, indefatigable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/indefatigable/thesaurus/synonyms>.
MLASmart Define. "indefatigable thesaurus" 10 April 2015. Web. 23 September 2026. <https://smartdefine.org/indefatigable/thesaurus/synonyms>