210 entries under hard topic. ×

1
mechanical(adjective, firm, solid, stiff)
1
mortified(adjective, strong, tough, severe)
1
numbed(adjective, firm, solid, stiff)
1
petrified(adjective, firm, solid, rigid)
1
rheumatic(adjective, firm, solid, stiff)
1
serious(adjective, strong, tough, severe)
1
soulless(adjective, careless, indifferent, cruel)
1
spiritless(adjective, careless, indifferent, cruel)
1
starchy(adjective, strong, firm, solid)
1
stiff as a board(expression, adjective, idiom, firm)
1
stout(adjective, strong, tough, firm)
1
thick(adjective, strong, tough, firm)
1
thick-skinned(adjective, mean, careless, indifferent)
1
thickened(adjective, firm, solid, stiff)
1
torpid(adjective, careless, indifferent, cruel)
1
tough nut to crack(expression, adjective, idiom, mean)
1
toughened(adjective, careless, indifferent, cruel)
1
unbreakable(adjective, strong, severe, firm)
1
unemotional(adjective, mean, harsh, unfeeling)
1
unimpressible(adjective, mean, harsh, stubborn)
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APASmart Define. (2016). inflexible thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/inflexible/thesaurus/synonyms
ChicagoSmart Define. 2016. "inflexible thesaurus" https://smartdefine.org/inflexible/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2016, inflexible thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/inflexible/thesaurus/synonyms>.
MLASmart Define. "inflexible thesaurus" 24 March 2016. Web. 30 September 2026. <https://smartdefine.org/inflexible/thesaurus/synonyms>