260 entries under adjective topic. ×

3
refractory(persistent, obstinate, insistent, dogged)
3
rock-ribbed(determined, resolute, uncompromising, unshakeable)
3
single-minded(tough, firm, unreasonable, grim)
3
stiff-necked(mean, hard, tough, firm)
3
stone(dull, lead, grim, hardness)
3
strict(hard, persistent, rigid, obstinate)
3
strong-willed(determined, resolution, resolute, uncompromising)
3
tough(mean, strong, hard, firm)
3
uncooperative(mean, hard, persistent, rigid)
3
unflinching(resolution, persistent, obstinate, insistent)
2
compact(set, strong, hard, firm)
2
dogged(mean, strong, hard, tough)
2
durable(firm, stiff, rigid)
2
ferric(strong, hard, tough, inflexible)
2
gritty
2
immutable(set, hard, stiff, rigid)
2
insensible(strong, hard, tough, inflexible)
2
red-blooded
2
rocky(set, strong, firm, stiff)
2
rude
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APASmart Define. (2015). iron thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/iron/thesaurus/synonyms
ChicagoSmart Define. 2015. "iron thesaurus" https://smartdefine.org/iron/thesaurus/synonyms (accessed September 27, 2026).
HarvardSmart Define 2015, iron thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/iron/thesaurus/synonyms>.
MLASmart Define. "iron thesaurus" 14 April 2015. Web. 27 September 2026. <https://smartdefine.org/iron/thesaurus/synonyms>