4
doubtfully(adverb, dishonestly, affectedly, insincerely, untruthfully)
4
furtively(adverb, false, lie, manner, doubtfully)
4
sharply(adverb, false, lie, manner, doubtfully)
4
shiftily(adverb, false, lie, manner, doubtfully)
4
slickly(adverb, false, lie, manner, doubtfully)
4
slyly(adverb, false, lie, manner, doubtfully)
4
sycophantically(adverb, false, lie, manner, doubtfully)
4
unctuously(adverb, false, lie, manner, doubtfully)
4
underhand(adverb, false, lie, manner, doubtfully)
4
underhanded(adverb, false, lie, manner, doubtfully)
4
untruly(adverb, dishonesty, manner, falsehood)
4
untruthfully(adverb, doubtfully, dishonestly, affectedly, insincerely)
3
slily(adverb, false, lie, manner, doubtfully)
2
ambiguously(adverb, doubtfully, dishonestly, affectedly, insincerely)
2
askance(adverb, doubtfully, dishonestly, affectedly, insincerely)
2
behind one's back(expression, adverb, doubtfully, dishonestly, affectedly)
2
disloyally(adverb, doubtfully, dishonestly, affectedly, insincerely)
2
faithlessly(adverb, doubtfully, dishonestly, affectedly, insincerely)
2
questionably(adverb, doubtfully, dishonestly, affectedly, insincerely)
2
traitorously(adverb, doubtfully, dishonestly, affectedly, insincerely)
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APASmart Define. (2016). sincerely thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/sincerely/thesaurus/antonyms
ChicagoSmart Define. 2016. "sincerely thesaurus" https://smartdefine.org/sincerely/thesaurus/antonyms (accessed September 24, 2026).
HarvardSmart Define 2016, sincerely thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/sincerely/thesaurus/antonyms>.
MLASmart Define. "sincerely thesaurus" 30 March 2016. Web. 24 September 2026. <https://smartdefine.org/sincerely/thesaurus/antonyms>