impenetrability Synonyms

impenetrableness imperviousness waterproofness vagueness toughness tightness thickness solidity resistance profundity profoundness perplexity opaqueness denseness reconditeness unfathomableness uncanniness numinousness impassability crowdedness arcaneness airtightness unintelligibility complicatedness unclearness mystique opacity obscurity mysteriousness equivocalness durability difficulty density deepness complexity compactness closeness ambiguousness ambiguity abstrusity esotericism hardness murkiness invulnerability intricacy inscrutableness inscrutability inflexibility incomprehensibility inaccessibility