196 entries under adjective topic. ×

3
round-the-clock(continue, continual)
3
safe(good, strong, solid, steady)
3
sedulous
3
timeless
2
abiding(set, clear, certain, fixed)
2
around-the-clock
2
boundless(certain, unchanging)
2
dedicated(strong, firm, determined, steady)
2
definite(good, clear, strong, solid)
2
dyed-in-the-wool(certain, true, constant, reliable)
2
enduring(set, clear, certain, steady)
2
guaranteed(certain, flawless, unquestionable, undisputable)
2
indomitable(strong, firm, determined, steady)
2
interminable
2
lasting(certain, fixed, reliable, continuous)
2
nonstop
2
ongoing
2
plodding(strong, firm, determined, steady)
2
plugging(strong, firm, determined, steady)
2
positive(good, clear, strong, solid)
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APASmart Define. (2016). unfailing thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/unfailing/thesaurus/synonyms
ChicagoSmart Define. 2016. "unfailing thesaurus" https://smartdefine.org/unfailing/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2016, unfailing thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/unfailing/thesaurus/synonyms>.
MLASmart Define. "unfailing thesaurus" 3 March 2016. Web. 29 September 2026. <https://smartdefine.org/unfailing/thesaurus/synonyms>