2
hole-and-corner
2
hugger-mugger
2
lubricious(adjective, honest, underhand)
2
lying(adjective, mean, bad, evil, false)
2
mendacious(adjective, false, dishonest, cunning, deceitful)
2
nefarious(adjective, dishonest, immoral, rotten, untrustworthy)
2
oblique(false, dishonest, cunning, deceitful, tricky)
2
prevaricating(adjective, dishonest)
2
private(secret, hidden, clandestine, underground, undisclosed)
2
roguish(adjective, false, deceitful, misleading, illusory)
2
rotten(adjective, low, dishonest, immoral, untrustworthy)
2
secretive(adjective, corrupt, dishonest, deceitful, secret)
2
slinking(sneaky, covert, secretive)
2
sneak(clandestine, underground, undisclosed)
2
ulterior(secret, hidden, clandestine, underground, privy)
2
unctuous(adjective, false, deceitful, lying, untruthful)
2
under-the-table(secret, hidden, clandestine, underground, sneaky)
2
undue(adjective, improper, excessive, unnecessary)
2
unprincipled(adjective, false, dishonest, immoral, deceitful)
2
unreliable(adjective, false, true, dishonest, deceitful)
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APASmart Define. (2016). underhanded thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/underhanded/thesaurus/synonyms
ChicagoSmart Define. 2016. "underhanded thesaurus" https://smartdefine.org/underhanded/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, underhanded thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/underhanded/thesaurus/synonyms>.
MLASmart Define. "underhanded thesaurus" 22 January 2016. Web. 22 September 2026. <https://smartdefine.org/underhanded/thesaurus/synonyms>