76 entries under strong topic. ×

6
tenacious(adjective, tough, firm, solid)
5
immovable(adjective, mean, hard, tough)
5
steadfast(adjective, tough, firm, determined)
4
able-bodied
4
cruel(adjective, hard, tough, inflexible)
4
lusty
4
obstinate(adjective, set, mean, hard)
4
set(verb, adjective, tough, firm)
4
vigorous
3
dense(adjective, set, hard, tough)
3
fast(adjective, tough, firm, solid)
3
heavy(adjective, hard, tough, inflexible)
3
tough(adjective, mean, hard, firm)
2
compact(adjective, set, hard, firm)
2
dogged(adjective, mean, hard, tough)
2
ferric(adjective, hard, tough, inflexible)
2
insensible(adjective, hard, tough, inflexible)
2
red-blooded
2
rocky(adjective, set, firm, stiff)
2
solid(adjective, set, hard, tough)
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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>