68 entries under hardened topic. ×

23
tough(adjective, hard, firm, solid, stiff)
21
adamantine(adjective, set, tough, firm, stiff)
14
hard(adjective, tough, firm, solid, cruel)
8
inaccessible(adjective, hard, unfeeling, unsympathetic, prepared)
7
stony(adjective, hard, firm, stiff, unfeeling)
6
rocky(adjective, set, firm, stiff, compact)
3
inflexible(adjective, set, strong, hard, tough)
3
resistant(adjective, hard, unfeeling, unsympathetic, prepared)
2
callous(adjective, set, hard, firm, stiff)
2
insensible(adjective, hard, unfeeling, unsympathetic)
2
obtuse(adjective, hard, unfeeling, unsympathetic, prepared)
2
stiff(adjective, set, hard, tough, firm)
2
unsusceptible(adjective, hard, unfeeling, unsympathetic)
1
accustomed(adjective, hard, unfeeling, unsympathetic, prepared)
1
benumbed(adjective, hard, unfeeling, unsympathetic, prepared)
1
case-hardened(adjective, hard, unfeeling, unsympathetic, prepared)
1
coldhearted(adjective, hard, unfeeling, unsympathetic, prepared)
1
contemptuous(adjective, hard, unfeeling, unsympathetic, prepared)
1
cruel(adjective, hard, unfeeling, unsympathetic)
1
disdainful(adjective, hard, unfeeling, unsympathetic, prepared)
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APASmart Define. (2015). impenetrable thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/impenetrable/thesaurus/synonyms
ChicagoSmart Define. 2015. "impenetrable thesaurus" https://smartdefine.org/impenetrable/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, impenetrable thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/impenetrable/thesaurus/synonyms>.
MLASmart Define. "impenetrable thesaurus" 10 April 2015. Web. 26 September 2026. <https://smartdefine.org/impenetrable/thesaurus/synonyms>