imperviousness imperviously • impest · · · Info · Definitions · Synonyms · Antonyms · Characters · · imperviousness · · Text Latin · · Script 14 · · Length Definitions · · · (noun) the quality of being impenetrable (by people or light or missiles etc.). Synonyms: impenetrability. · · Noun Definition 1 Synonyms · · · impenetrability · · Synonym 1 Antonyms · · · penetrability · · Antonym 0 perviousness · · Antonym 1 Characters · · e latin small letter e U+0065 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070 r latin small letter r U+0072 s latin small letter s U+0073 u latin small letter u U+0075 v latin small letter v U+0076