16
remorseless(adjective, mean, kind, severe, harsh)
16
unpitying(noun, adjective, mean, severe, harsh)
15
stony(adjective, person, mean, hard, tough)
15
vicious(adjective, mean, hard, evil, rough)
14
barbaric(adjective, rough, violent, cruel, vicious)
14
cold-blooded(adjective, person, mean, hard, tough)
14
ferocious(adjective, mean, hard, evil, rough)
14
fierce(adjective, mean, hard, tough, evil)
14
severe(adjective, appearance, mean, hard, tough)
13
implacable(adjective, appearance, mean, hard, tough)
13
relentless(adjective, appearance, mean, hard, tough)
12
brutish(adjective, hard, evil, nasty, harsh)
12
cutthroat(adjective, mean, harsh, cruel, vicious)
12
inexorable(adjective, appearance, mean, hard, tough)
12
mean(adjective, person, evil, nasty, difficult)
12
unyielding(adjective, appearance, mean, hard, tough)
11
bloodthirsty(adjective, severe, evil, nasty, harsh)
11
grim(adjective, appearance, mean, hard, tough)
11
insensitive(adjective, hard, tough, severe, harsh)
11
vindictive(adjective, person, mean, hard, tough)
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APASmart Define. (2016). merciless thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/merciless/thesaurus/synonyms
ChicagoSmart Define. 2016. "merciless thesaurus" https://smartdefine.org/merciless/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2016, merciless thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/merciless/thesaurus/synonyms>.
MLASmart Define. "merciless thesaurus" 31 March 2016. Web. 26 September 2026. <https://smartdefine.org/merciless/thesaurus/synonyms>