94 entries under tough topic. ×

4
resolute(adjective, calm, strong, secure)
4
strapping(adjective, person, body, strong, sound)
4
stubborn(adjective, strong, secure, firm)
3
able-bodied(adjective, person, body, strong, sound)
3
athletic(adjective, person, body, strong, sound)
3
enduring(adjective, calm, strong, sound)
3
hardened(adjective, set, strong, hard)
3
inelastic(adjective, hard, severe, firm)
3
obstinate(adjective, strong, firm, determined)
3
unswerving(adjective, strong, complete, smooth)
2
active(adjective, strong, sound, heavy)
2
fit(adjective, strong, hard, sound, complete)
2
forcible(adjective, clear, strong, sound)
2
heavy-duty(adjective, strong, sound, heavy)
2
iron(adjective, set, strong, hard)
2
reinforced(adjective, strong, sound, heavy)
2
sinewy(adjective, strong, hard, sound)
2
tenacious(adjective, strong, sound, secure)
2
well(adjective, adverb, strong, complete)
1
hard as nails(expression, adjective, idiom, set, strong)
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APASmart Define. (2016). solid thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/solid/thesaurus/synonyms
ChicagoSmart Define. 2016. "solid thesaurus" https://smartdefine.org/solid/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, solid thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/solid/thesaurus/synonyms>.
MLASmart Define. "solid thesaurus" 29 March 2016. Web. 25 September 2026. <https://smartdefine.org/solid/thesaurus/synonyms>