Antonyms of noun perviousness

1 sense of perviousness

Sense 1
penetrability, perviousness -- (the quality of being penetrable (by people or light or missiles etc.))
       Antonym of imperviousness (Sense 1)
      => impenetrability, imperviousness -- (the quality of being impenetrable (by people or light or missiles etc.))

Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun perviousness

1 sense of perviousness

Sense 1
penetrability, perviousness -- (the quality of being penetrable (by people or light or missiles etc.))
       => quality -- (an essential and distinguishing attribute of something or someone; "the quality of mercy is not strained"--Shakespeare)