6
glum(adjective, rough, nasty, dark, unpleasant)
6
hideous(adjective, appearance, evil, awful, violent)
6
insidious
6
left-handed(adjective, awkward, black, baleful, bodeful)
6
mischievous(adjective, evil, nasty, threatening, injurious)
6
morose(adjective, rough, nasty, sad, dark)
6
saturnine(adjective, rough, nasty, dark, unpleasant)
6
sorry(adjective, sad, unhappy, unpleasant, sorrow)
6
vile(adjective, mean, bad, wrong, evil)
5
vengeful(adjective, evil, nasty, negative, behavior)
5
alarming(adjective, hard, severe, offensive, distressing)
5
aloof(adjective, person, unwarmhearted)
5
banemalenteous(adjective, person, unwarmhearted)
5
barbaric(adjective, person, unwarmhearted)
5
bodeful(adjective, person, feelings, black, baleful)
5
brutal(adjective, person, unwarmhearted)
5
calamitous(adjective, evil, injurious, damaging, destructive)
5
cold-blooded(adjective, person, unwarmhearted)
5
cool(adjective, person, unwarmhearted)
5
criminal(adjective, wicked)
10 years ago|29k views|share |citing 
APASmart Define. (2016). sinister thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/sinister/thesaurus/synonyms
ChicagoSmart Define. 2016. "sinister thesaurus" https://smartdefine.org/sinister/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, sinister thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/sinister/thesaurus/synonyms>.
MLASmart Define. "sinister thesaurus" 3 April 2016. Web. 24 September 2026. <https://smartdefine.org/sinister/thesaurus/synonyms>