14
forever(adverb, always, ever, constantly, continually)
4
infallibly(adverb, absolutely, certainly, clearly, definitely)
4
invariably(adverb, uniformity, perpetually)
4
surely(adverb, absolutely, clearly, plainly, constantly)
3
always
3
consistently(adverb, faithfully, dependably)
3
constantly
3
continually
3
staunchly(adverb, faithfully)
3
unerringly(adverb, absolutely, certainly, clearly, definitely)
2
beyond shadow of doubt(expression, idiom, adverb, absolutely, certainly)
2
certainly
2
come what may(expression, idiom, adverb, absolutely, certainly)
2
faithfully
2
fixedly(adverb, absolutely, certainly, clearly, definitely)
2
inexhaustibly
2
irrefutably(adverb, absolutely, certainly, clearly, definitely)
2
rain or shine(expression, idiom, adverb, absolutely, certainly)
2
reliably
2
unshakably(adverb, absolutely, certainly, clearly, definitely)
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APASmart Define. (2013). unfailingly thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/unfailingly/thesaurus/synonyms
ChicagoSmart Define. 2013. "unfailingly thesaurus" https://smartdefine.org/unfailingly/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2013, unfailingly thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/unfailingly/thesaurus/synonyms>.
MLASmart Define. "unfailingly thesaurus" 17 June 2013. Web. 20 September 2026. <https://smartdefine.org/unfailingly/thesaurus/synonyms>