2
hardness(noun, protection, security, cruelty, rigidity)
2
inscrutability
2
inscrutableness
2
intricacy(noun, incomprehensibility)
2
perplexity
2
profundity
2
reconditeness
2
resistance(noun, protection, security, rigidity, hardness)
2
toughness(noun, protection, security, rigidity, hardness)
1
consistency(noun, mass, bulk, density, thickness)
1
body(noun, mass, bulk, density, thickness)
1
compactness(noun, mass, protection, security, rigidity)
1
complication
1
concretion(noun, mass, bulk, density, thickness)
1
congestion
1
consistence
1
constipation
1
denseness(noun, mass, bulk, density, thickness)
1
dimness
1
durability(noun, protection, security, rigidity, hardness)
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APASmart Define. (2015). impenetrability thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/impenetrability/thesaurus/synonyms
ChicagoSmart Define. 2015. "impenetrability thesaurus" https://smartdefine.org/impenetrability/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, impenetrability thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/impenetrability/thesaurus/synonyms>.
MLASmart Define. "impenetrability thesaurus" 14 April 2015. Web. 22 September 2026. <https://smartdefine.org/impenetrability/thesaurus/synonyms>