150 entries under adjective topic. ×

17
immovable(strong, hard, tough, cruel)
17
implacable(strong, hard, tough, resist)
15
grim(strong, hard, tough, resist)
14
determined(strong, hard, tough, severe)
14
resolute(hard, determined, rigid, strict)
14
steely(strong, hard, tough, firm)
13
stony(firm, stiff, rigid, stubborn)
12
iron(set, strong, hard, tough)
10
stern(determined, resolute, uncompromising, unshakeable)
10
stiff(set, firm, harsh, determined)
9
rocky(set, firm, stiff, compact)
9
uncompliant(tough, firm, resist, determined)
8
fixed(tough, severe, determined, resolute)
8
incompliant(resist, determined, resolute, persistent)
8
obstinate(cruel, determined, resolute, pitiless)
8
set(severe, firm, harsh, determined)
7
brassbound(resist, determined, resolute, persistent)
7
die-hard(resist, determined, resolute, persistent)
7
hardheaded(strong, hard, tough, firm)
7
pat(determined, resolute, uncompromising, unshakeable)
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APASmart Define. (2015). adamantine thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/adamantine/thesaurus/synonyms
ChicagoSmart Define. 2015. "adamantine thesaurus" https://smartdefine.org/adamantine/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, adamantine thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/adamantine/thesaurus/synonyms>.
MLASmart Define. "adamantine thesaurus" 10 April 2015. Web. 26 September 2026. <https://smartdefine.org/adamantine/thesaurus/synonyms>