10
intransigent(adjective, tough, resist, determined, resolute)
10
smooth(verb, move, hold, press, push)
9
grim(adjective, tough, firm, resist, determined)
9
stern(adjective, characteristic, persistent, obstinate, insistent)
8
flatten(verb, activity, move, hold, calm)
8
determined(adjective, strong, hard, tough, firm)
8
fetter(noun, verb, free, restraint, bond)
8
strong(adjective, hard, tough, firm, determined)
7
indomitable(adjective, characteristic, strong, hard, tough)
7
manacle(noun, verb, free, restraint, shackle)
7
robust(adjective, strong, hard, tough, inflexible)
7
shackle(noun, verb, free, restraint, shackles)
7
uncompliant(adjective, tough, resist, unreasonable, grim)
6
bond(noun, free, restraint, shackle, metal)
6
ferrous(adjective, strong, hard, tough, inflexible)
6
incompliant(adjective, resist, determined, resolute, persistent)
6
irons(noun, shackles, chains, manacles, handcuff)
6
mangle(verb, move, hold, smooth, push)
6
restraint(noun, free, shackle, shackles, chains)
6
steely(adjective, dull, strong, hard, tough)
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APASmart Define. (2015). iron thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/iron/thesaurus/synonyms
ChicagoSmart Define. 2015. "iron thesaurus" https://smartdefine.org/iron/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, iron thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/iron/thesaurus/synonyms>.
MLASmart Define. "iron thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/iron/thesaurus/synonyms>