308 entries under adjective topic. ×

1
hard-bitten(hard, unfeeling, unsympathetic, hardened)
1
hard-boiled(hard, unfeeling, unsympathetic, hardened)
1
hardhearted(hard, cruel, unfeeling, unsympathetic)
1
heartless(hard, cruel, unfeeling, unsympathetic)
1
huge
1
impassive(hard, unfeeling, unsympathetic, hardened)
1
impious(hard, unfeeling, unsympathetic, prepared)
1
indivisible
1
indurated(set, hard, firm, stiff)
1
intractable
1
intricate
1
inured(hard, unfeeling, unsympathetic, hardened)
1
involved
1
irreverent(hard, unfeeling, unsympathetic, prepared)
1
jelled(set, hard, tough, solid)
1
jellied(set, solid, heavy, deep)
1
knotty
1
labored
1
laborious
1
leaden
11 years ago|15k views|share |citing 
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>