1
devoted(adjective, resolute)
1
disciplinary(adjective, strong, hard, tough, severe)
1
dispassionate
1
dog-eat-dog(adjective, mean, hard, severe, harsh)
1
dour
1
dyed-in-the-wool(adjective, set, strong, hard, tough)
1
earnest(adjective, resolute)
1
excruciating(adjective, evil, nasty, harsh, vicious)
1
faithful(adjective, resolute)
1
fearless(adjective, resolute)
1
feral(adjective, mean, harsh, violent, cruel)
1
forbidding(adjective, appearance, strong, hard, tough)
1
frightful(adjective, appearance, violent, terrible, cruel)
1
frowning(adjective, strong, hard, tough, severe)
1
go for broke(expression, adjective, idiom, harsh, cruel)
1
gratuitous(adjective, mean, severe, harsh, cruel)
1
grudgeful
1
hang-tough(adjective, strong, hard, tough, harsh)
1
hang in(expression, adjective, harsh, cruel, determined)
1
hanging tough(expression, adjective, mean, hard, rigid)
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APASmart Define. (2016). implacable thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/implacable/thesaurus/synonyms
ChicagoSmart Define. 2016. "implacable thesaurus" https://smartdefine.org/implacable/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2016, implacable thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/implacable/thesaurus/synonyms>.
MLASmart Define. "implacable thesaurus" 24 March 2016. Web. 21 September 2026. <https://smartdefine.org/implacable/thesaurus/synonyms>