4
venal(adjective, low, dishonest, immoral, rotten)
3
bad to the bone
3
crooked(adjective, wrong, corrupt, vicious, dishonest)
3
curst(adjective, dislike, disgusting, hate, yuck)
3
debased(adjective, wrong, evil, wicked, immoral)
3
invidious(adjective, dislike, disgusting, hate, yuck)
3
malicious(adjective, wicked)
3
nefariuos(adjective, dislike, disgusting, hate, yuck)
3
perfidious(adjective, dishonest, immoral, rotten, untrustworthy)
3
pernicious(adjective, bad, hurtful)
3
picayune(adjective, dislike, disgusting, hate, yuck)
3
questionable(adjective, disreputable)
3
repellent(adjective, evil, offensive, unpleasant, base)
3
revolting(adjective, bad, evil, offensive, unpleasant)
3
shady(adjective, wrong, corrupt, vicious, vile)
3
shifty(adjective, disreputable)
3
slimy(adjective, dislike, disgusting, hate, yuck)
3
sordid
3
unethical(adjective, bad, wrong, evil, corrupt)
2
abject(evil, shameful, depraved)
10 years ago|20k views|share |citing 
APASmart Define. (2015). nefarious thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/nefarious/thesaurus/synonyms
ChicagoSmart Define. 2015. "nefarious thesaurus" https://smartdefine.org/nefarious/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, nefarious thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/nefarious/thesaurus/synonyms>.
MLASmart Define. "nefarious thesaurus" 8 October 2015. Web. 22 September 2026. <https://smartdefine.org/nefarious/thesaurus/synonyms>