45 entries under untiring topic. ×

11
staunch(adjective, strong, tough, fit, firm)
11
steady(adjective, strong, firm, determined, resolute)
11
vigorous(adjective, strong, sound, tough, fit)
10
unswerving(adjective, set, strong, firm, determined)
9
constant(adjective, strong, firm, determined, steady)
9
pertinacious(adjective, strong, firm, determined, steady)
8
firm(adjective, strong, tough, fit, solid)
8
patient(noun, adjective, strong, firm, determined)
8
relentless(adjective, resolute)
8
unflinching(adjective, set, strong, firm, determined)
8
unremitting(adjective, strong, firm, determined, steady)
7
painstaking(adjective, activity)
7
strenuous(adjective, strong, moving, difficult, energetic)
5
active(adjective, strong, moving, difficult, energetic)
5
dynamic(adjective, strong, moving, lively, active)
5
unceasing(adjective, strong, firm, determined, steady)
2
incessant(adjective, strong, firm, determined, steady)
1
ball of fire(expression, adjective, idiom, strong, lively)
1
bound and determined
1
dead set on
11 years ago|10k views|share |citing 
APASmart Define. (2015). indefatigable thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/indefatigable/thesaurus/synonyms
ChicagoSmart Define. 2015. "indefatigable thesaurus" https://smartdefine.org/indefatigable/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2015, indefatigable thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/indefatigable/thesaurus/synonyms>.
MLASmart Define. "indefatigable thesaurus" 10 April 2015. Web. 28 September 2026. <https://smartdefine.org/indefatigable/thesaurus/synonyms>