10
assiduous(adjective, persistent, continuous)
10
unwearied(adjective, strong, continue, firm, energetic)
9
diligent(adjective, persistent, persevering, tenacious)
9
energetic(adjective, determined, active, vigorous, full)
8
fixed(adjective, persistent)
8
inexhaustible(adjective, strong, continue, firm, energetic)
8
obstinate(adjective, tenacious)
8
persisting(adjective, continuous)
8
undeviating(adjective, persistent, perseverance)
8
unremitting(adjective, strong, firm, energetic, determined)
7
faithful(adjective, firm, certain, cheerful, comfortable)
7
firm(adjective, strong, tough, fit, solid)
7
industrious(adjective, strong, difficult, energetic, lively)
7
loyal(adjective, strong, firm, certain, constant)
7
undaunted(adjective, tenacious)
7
unflinching(adjective, set, strong, firm, energetic)
6
dynamic(adjective, strong, moving, lively, active)
6
enduring(adjective, set, strong, steady, constant)
6
indomitable(adjective, strong, firm, determined, steady)
6
pertinacious(adjective, strong, firm, energetic, determined)
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APASmart Define. (2015). unflagging thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/unflagging/thesaurus/synonyms
ChicagoSmart Define. 2015. "unflagging thesaurus" https://smartdefine.org/unflagging/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, unflagging thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/unflagging/thesaurus/synonyms>.
MLASmart Define. "unflagging thesaurus" 14 April 2015. Web. 21 September 2026. <https://smartdefine.org/unflagging/thesaurus/synonyms>