2
doubtlessly(adverb, certainly, faithfully, loyally, stalwartly)
2
fixedly(adverb, hard, firm, obstinately, stubbornly)
2
heartily(adverb, tenaciously)
2
indefatigably(adverb, tenaciously)
2
positively(adverb, certainly, loyally, stalwartly)
2
seriously(adverb, fast, intensely, fiercely, violently)
2
stalwartly(adverb, faithfully, loyally)
2
stiffly(adverb, tenaciously)
2
stubbornly(adverb, tenaciously)
2
tight(adverb, hard, firm, fast, severely)
2
tirelessly(adverb, tenaciously)
2
truly(adverb, tenaciously)
2
undauntedly(adverb, tenaciously)
2
unfalteringly(adverb, resolutely, determinedly, persistently, loyally)
1
abidingly
1
actively(adverb, fast, intensely, fiercely, violently)
1
adamantly
1
assiduously
1
boldly(adverb, tenaciously)
1
bona fide
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APASmart Define. (2015). steadfastly thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/steadfastly/thesaurus/synonyms
ChicagoSmart Define. 2015. "steadfastly thesaurus" https://smartdefine.org/steadfastly/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, steadfastly thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/steadfastly/thesaurus/synonyms>.
MLASmart Define. "steadfastly thesaurus" 14 April 2015. Web. 21 September 2026. <https://smartdefine.org/steadfastly/thesaurus/synonyms>