210 entries under hard topic. ×

12
solid(adjective, strong, secure, smooth)
11
austere(adjective, strong, tough, severe)
11
stiff-necked(adjective, mean, strong, tough)
10
hardened(adjective, person, tough, firm)
10
hardheaded(adjective, strong, tough, cold)
10
immutable(adjective, set, secure, rough)
10
stringent(adjective, severe, rough, difficult)
9
callous(adjective, person, tough, rough)
9
perverse(adjective, mean, firm, deliberate)
9
unforgiving(adjective, person, rough, harsh)
9
unsympathetic(adjective, mean, careless, indifferent)
8
flinty(adjective, strong, tough, severe)
8
hard-line(adjective, strong, tough, severe)
8
merciless(adjective, person, rough, harsh)
7
cruel(adjective, strong, tough, severe)
7
hanging tough(expression, adjective, mean, determined)
7
hard-boiled(adjective, person, mean, strong)
7
indomitable(adjective, set, strong, tough)
7
precise(adjective, severe, rough, difficult)
7
resistant(adjective, firm, determined, resolute)
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APASmart Define. (2016). inflexible thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/inflexible/thesaurus/synonyms
ChicagoSmart Define. 2016. "inflexible thesaurus" https://smartdefine.org/inflexible/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2016, inflexible thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/inflexible/thesaurus/synonyms>.
MLASmart Define. "inflexible thesaurus" 24 March 2016. Web. 29 September 2026. <https://smartdefine.org/inflexible/thesaurus/synonyms>