18
vicious(adjective, mean, hard, evil, rough)
17
hard-hearted(adjective, mean, hard, tough, severe)
17
barbaric(adjective, animal, mean, rude, violent)
17
severe(adjective, appearance, mean, hard, tough)
17
unpitying(adjective, mean, severe, harsh, cruel)
16
uncompassionate(adjective, animal, mean, hard, tough)
15
bloodthirsty(adjective, severe, evil, nasty, harsh)
15
brutish(adjective, evil, nasty, harsh, rude)
15
implacable(adjective, animal, appearance, mean, hard)
15
inexorable(adjective, appearance, mean, hard, tough)
15
unforgiving(adjective, mean, hard, tough, severe)
14
inhumane(adjective, animal, mean, hard, tough)
14
tough(adjective, strong, hard, severe, rough)
14
unyielding(adjective, appearance, mean, strong, hard)
12
sadistic(adjective, mean, evil, nasty, harsh)
12
unkind(adjective, animal, mean, hard, tough)
11
fiendish(adjective, animal, mean, nasty, cruel)
11
grim(adjective, animal, appearance, mean, hard)
11
insensitive(adjective, hard, tough, severe, harsh)
11
stern(adjective, appearance, mean, hard, severe)
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APASmart Define. (2016). ruthless thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/ruthless/thesaurus/synonyms
ChicagoSmart Define. 2016. "ruthless thesaurus" https://smartdefine.org/ruthless/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, ruthless thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/ruthless/thesaurus/synonyms>.
MLASmart Define. "ruthless thesaurus" 24 March 2016. Web. 22 September 2026. <https://smartdefine.org/ruthless/thesaurus/synonyms>