1
expeditiously(vigorously, earnestly, actively, hastily, carefully)
1
expertly
1
fatal
1
feelingly(adverb, severely, thoroughly, completely, intensely)
1
ferociously(adverb, fast, sprightly, severely, intensely)
1
fervidly
1
fiercely(adverb, fast, severely, intensely, vigorously)
1
finely
1
fixedly
1
flagitiously
1
for a certainty(expression, idiom)
1
forcibly(adverb, fast, sprightly, severely, intensely)
1
formally
1
forsooth
1
frantically(adverb, fast, sprightly, severely, intensely)
1
fully
1
fundamentally
1
genuinely(adverb, severely, really, thoroughly, completely)
1
gloomy
1
grandly
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APASmart Define. (2016). seriously thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/seriously/thesaurus/synonyms
ChicagoSmart Define. 2016. "seriously thesaurus" https://smartdefine.org/seriously/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2016, seriously thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/seriously/thesaurus/synonyms>.
MLASmart Define. "seriously thesaurus" 31 March 2016. Web. 23 September 2026. <https://smartdefine.org/seriously/thesaurus/synonyms>