'Imperviousness' definitions:

Definition of 'imperviousness'

From: WordNet
noun
The quality of being impenetrable (by people or light or missiles etc.) [syn: impenetrability, imperviousness] [ant: penetrability, perviousness]

Definition of 'Imperviousness'

From: GCIDE
  • Impervious \Im*per"vi*ous\, a. [L. impervius; pref. im- not + per through + via way. See Voyage.] Not pervious; not admitting of entrance or passage through; as, a substance impervious to water or air. [1913 Webster]
  • This gulf impassable, impervious. --Milton. [1913 Webster]
  • The minds of these zealots were absolutely impervious. --Macaulay.
  • Syn: Impassable; pathless; impenetrable; imperviable; impermeable. -- {Im*per"vi*ous*ly}, adv. -- {Im*per"vi*ous*ness}, n. [1913 Webster]