Synonyms|713Antonyms|152|Broader|9Narrower|8Related|663

98 entries under hard topic. ×

3
inflexible(adjective, set, strong, tough)
3
resistant(adjective, unfeeling, unsympathetic, prepared)
3
rigid(adjective, set, strong, tough)
3
strong(adjective, close, set, secure)
2
callous(adjective, set, firm, stiff)
2
compacted(adjective, set, strong, firm)
2
concentrated(adjective, set, tough, firm)
2
hardened(adjective, set, strong, tough)
2
insensible(adjective, unfeeling, unsympathetic, hardened)
2
obtuse(adjective, unfeeling, unsympathetic, prepared)
2
solidified(adjective, set, tough, solid)
2
stiff(adjective, set, tough, firm)
2
unsusceptible(adjective, unfeeling, unsympathetic, hardened)
1
accustomed(adjective, unfeeling, unsympathetic, prepared)
1
benumbed(adjective, unfeeling, unsympathetic, prepared)
1
case-hardened(adjective, unfeeling, unsympathetic, prepared)
1
close-grained(adjective, close, set, tough)
1
coldhearted(adjective, unfeeling, unsympathetic, prepared)
1
congealed(adjective, set, tough, solid)
1
contemptuous(adjective, unfeeling, unsympathetic, prepared)
For more, visit Impenetrable on Power Thesaurus
11 years ago|15k views|share |citing 
APASmart Define. (2015). impenetrable thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/impenetrable/thesaurus/synonyms
ChicagoSmart Define. 2015. "impenetrable thesaurus" https://smartdefine.org/impenetrable/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, impenetrable thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/impenetrable/thesaurus/synonyms>.
MLASmart Define. "impenetrable thesaurus" 10 April 2015. Web. 25 September 2026. <https://smartdefine.org/impenetrable/thesaurus/synonyms>