4
slippery(adjective, smooth, sharp, false, dishonest)
4
traitorous(adjective, mean, smooth, dishonest, cunning)
3
double-crossing(adjective, characteristic, dishonest, cunning, deceit)
3
double-dealing(adjective, mean, smooth, dishonest, cunning)
3
elusive(adjective, mean, smooth, deception, cunning)
3
fraudulent(adjective, false, dishonest, cunning, deceitful)
3
two-timing(adjective, characteristic, dishonest, cunning, deceit)
3
unethical(adjective, dishonest, cunning, deceitful, sneaky)
2
backhanded(adjective, characteristic, guile, insidiousness)
1
like a snake in the grass(expression, idiom, characteristic, guile, insidiousness)
1
alluring(adjective, feature, characteristic, trait)
1
alluring but harmful(expression, characteristic, property, alluring)
1
beguiling but harmful(expression, characteristic, property, alluring)
1
ensnaring(adjective, characteristic, guile, insidiousness)
1
gradually causing harm(expression, characteristic, property, alluring)
1
harmful but enticing(expression, characteristic, property, alluring)
1
indirect(adjective, feature, behavior, guile)
1
secretly causing harm(expression, characteristic, property, alluring)
1
seductive(adjective, characteristic, harm, seduction)
1
stealthily deceitful(expression, characteristic, property, alluring)
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APASmart Define. (2015). insidious thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/insidious/thesaurus/synonyms
ChicagoSmart Define. 2015. "insidious thesaurus" https://smartdefine.org/insidious/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, insidious thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/insidious/thesaurus/synonyms>.
MLASmart Define. "insidious thesaurus" 14 April 2015. Web. 25 September 2026. <https://smartdefine.org/insidious/thesaurus/synonyms>