79 entries under hard topic. ×

1
arthritic(adjective, firm, solid, tense)
1
benumbed(adjective, firm, solid, tense)
1
brittle(adjective, firm, solid, tense)
1
buckram(adjective, firm, solid, tense)
1
cemented(adjective, firm, solid, tense)
1
chilled(adjective, firm, solid, tense)
1
concrete(tough, solid, rigid, inflexible)
1
congealed(adjective, tough, firm, solid)
1
contracted(adjective, firm, solid, tense)
1
creaky(adjective, firm, solid, tense)
1
drastic(adjective, severe, rough, harsh)
1
ferocious(adjective, severe, rough, harsh)
1
fierce(adjective, severe, rough, harsh)
1
frozen(adjective, firm, solid, tense)
1
graceless(adjective, firm, solid, tense)
1
hardened(adjective, tough, firm, solid)
1
heavy(tough, solid, rigid, inflexible)
1
immalleable(adjective, firm, solid, stiff)
1
immutable(adjective, severe, rough, harsh)
1
impervious(tough, solid, rigid, inflexible)
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APASmart Define. (2015). refractory thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/refractory/thesaurus/synonyms
ChicagoSmart Define. 2015. "refractory thesaurus" https://smartdefine.org/refractory/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, refractory thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/refractory/thesaurus/synonyms>.
MLASmart Define. "refractory thesaurus" 10 April 2015. Web. 24 September 2026. <https://smartdefine.org/refractory/thesaurus/synonyms>