1
flat(adjective, continuous)
1
flintlike(adjective, tenacious)
1
forcible(adjective, strong, moving, lively, active)
1
full of beans(expression, adjective, idiom, active, peppy)
1
gapless(adjective, continuous)
1
go-go(adjective, strong, firm, determined, steady)
1
grind(adjective, strong, firm, energetic, determined)
1
habitual(adjective, continuous)
1
hale(strong, fit, healthy, well, robust)
1
hardy(adjective, strong, tough, fit, lively)
1
hell-bent(adjective, untiring)
1
high-powered(adjective, strong, moving, lively, active)
1
homogeneous(adjective, continuous)
1
hyper
1
inalterable
1
intense
1
intrepid
1
invariable(adjective, continuous)
1
iron-willed(adjective, resolute)
1
ironclad(adjective, untiring)
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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>