8
poisonous(adjective, bad, evil, nasty, harmful)
8
atrocious(adjective, evil, awful, terrible, dreadful)
8
crooked(adjective, false, corrupt, immoral, deceitful)
8
cruel(adjective, person, appearance, terrible, hopeless)
8
deleterious(adjective, bad, evil, nasty, harmful)
8
diabolic
8
heinous(adjective, evil, vice)
8
hurtful(adjective, bad, nasty, offensive, negative)
8
ill-omened(adjective, black, warning, threatening, unfavorable)
8
ill-starred(adjective, sad, unhappy, unpleasant, woe)
8
inconsiderate(adjective, person, negative, behavior, unwarmhearted)
8
indecent(adjective, person, wicked, unwarmhearted)
8
iniquitous(adjective, wicked)
8
merciless(adjective, person, evil, negative, behavior)
8
satanic(adjective, evil)
8
stern(adjective, person, dark, terrible, negative)
8
sullen(adjective, mean, bad, wrong, evil)
8
ugly(adjective, person, unpleasant, feelings, horrible)
8
untoward(adjective, sad, unhappy, unpleasant, woe)
8
wretched(adjective, sad, unhappy, unpleasant, horrible)
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APASmart Define. (2016). sinister thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/sinister/thesaurus/synonyms
ChicagoSmart Define. 2016. "sinister thesaurus" https://smartdefine.org/sinister/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, sinister thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/sinister/thesaurus/synonyms>.
MLASmart Define. "sinister thesaurus" 3 April 2016. Web. 22 September 2026. <https://smartdefine.org/sinister/thesaurus/synonyms>