- Definitions|2
- Thesaurus|1.5k
- Abbreviations|0
98 entries under hard topic. ×
| indifferent(adjective, cruel, unfeeling, unsympathetic) | |
| indurate(adjective, set, strong, firm) | |
| inelastic(solid, rigid) | |
| insensate(adjective, unfeeling, unsympathetic, hardened) | |
| insensitive(adjective, cruel, unfeeling, unsympathetic) | |
| insentient(adjective, unfeeling, unsympathetic, hardened) | |
| iron(adjective, set, strong, firm) | |
| refractory(solid, rigid) | |
| soulless(adjective, unfeeling, unsympathetic, hardened) | |
| spiritless(adjective, unfeeling, unsympathetic, hardened) | |
| sturdy(solid, rigid) | |
| thick-skinned(adjective, unfeeling, unsympathetic, hardened) | |
| torpid(adjective, unfeeling, unsympathetic, hardened) | |
| unaffected(adjective, unfeeling, unsympathetic, hardened) | |
| unconcerned(adjective, unfeeling, unsympathetic, hardened) | |
| unimpressionable(adjective, unfeeling, unsympathetic, hardened) | |
| unresponsive(adjective, unfeeling, unsympathetic, hardened) | |
| unsympathetic(adjective, cruel, unfeeling, hardened) |
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| APA | Smart Define. (2015). impenetrable thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/impenetrable/thesaurus/synonyms |
| Chicago | Smart Define. 2015. "impenetrable thesaurus" https://smartdefine.org/impenetrable/thesaurus/synonyms (accessed September 26, 2026). |
| Harvard | Smart Define 2015, impenetrable thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/impenetrable/thesaurus/synonyms>. |
| MLA | Smart Define. "impenetrable thesaurus" 10 April 2015. Web. 26 September 2026. <https://smartdefine.org/impenetrable/thesaurus/synonyms> |