4
cement
4
copper(noun, element)
4
cruel(adjective, strong, hard, tough, inflexible)
4
granite(adjective, lead, hardness, leaden, mousy)
4
handcuffs(noun, bond, metal)
4
heart of oak(expression, idiom, strength, hardness)
4
hearty
4
hidebound(adjective, persistent, obstinate, stubborn, unbending)
4
iron out(verb, expression, phrasal verb, press)
4
ironing(noun, verb, calm, quiet, reheat)
4
lead(noun, adjective, dull, element, grim)
4
level(verb, move, hold, calm, quiet)
4
lusty(adjective, strong)
4
obstinate(adjective, set, mean, strong, hard)
4
pig(noun, hard, metal)
4
platinum(noun, element)
4
potassium(noun, element)
4
resolved(adjective, determined, resolution, resolute, persistent)
4
roll(verb, smoothness)
4
set(verb, adjective, strong, tough, firm)
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APASmart Define. (2015). iron thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/iron/thesaurus/synonyms
ChicagoSmart Define. 2015. "iron thesaurus" https://smartdefine.org/iron/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, iron thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/iron/thesaurus/synonyms>.
MLASmart Define. "iron thesaurus" 14 April 2015. Web. 24 September 2026. <https://smartdefine.org/iron/thesaurus/synonyms>