20 entries under mean topic. ×

17
underhand(adjective, deceitful, characteristic, cunning, guile)
16
designing(adjective, cunning, tricky, guile, insidiousness)
14
stealthy(adjective, sneaky, guile, insidiousness, characteristic)
11
surreptitious(adjective, sneaky, guile, insidiousness, characteristic)
10
smooth(adjective, guile, insidiousness, characteristic)
8
arch(cunning, adjective, characteristic, smooth)
8
sneaking(adjective, guile, insidiousness, characteristic, tricky)
7
furtive(adjective, smooth, dishonest, deceitful)
6
canny(adjective, smooth, sharp, cunning)
5
secret(adjective, sneaky, characteristic, smooth)
5
sharp(adjective, smooth, cunning, deceitful)
5
unscrupulous(adjective, smooth, dishonest, cunning)
4
delusive(adjective, characteristic, smooth, deception)
4
dishonorable(adjective, characteristic, smooth, dishonest)
4
illusory(adjective, characteristic, smooth, deception)
4
mischievous(adjective, smooth, wicked, cunning)
4
plotting(adjective, smooth, cunning, knowing)
4
traitorous(adjective, smooth, dishonest, cunning)
3
double-dealing(adjective, smooth, dishonest, cunning)
3
elusive(adjective, smooth, deception, cunning)
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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>