impenetrability Synonyms

impenetrableness imperviousness vagueness unanswerability toughness tightness thickness spissitude solidity resistance profundity profoundness perplexity opaqueness denseness reconditeness mystique waterproofness unfathomableness uncanniness numinousness impassability crowdedness arcaneness airtightness impermeableness unintelligibility complicatedness unclearness opacity obscurity mysteriousness illegibility hardness equivocalness durability difficulty density deepness complexity compactness closeness ambiguousness ambiguity abstruseness impermeability imporosity murkiness invulnerableness invulnerability