[1] : The Collaborative International Dictionary of English v.0.48

impenetrability \impen`etrabil"ity\, n. cf. f.
   imp'en'etrabilit'e.
   1. quality of being impenetrable.
      1913 webster

   2. physics that property in virtue of which two portions of
      matter can not at the same time occupy the same portion of
      space.
      1913 webster

   3. insusceptibility of intellectual or emotional impression;
      obtuseness; stupidity; coldness.
      1913 webster

[2] : WordNet (r) 2.0

impenetrability
     n 1: resistance to penetration by a liquid syn: imperviousness
          ant: penetrability, penetrability
     2: incomprehensibility by virtue of being too dense to
        understand syn: impenetrableness
see also:
imperviousness penetrability impenetrableness 

Impenetrability >> I Words
Impenetrability, definition of term: Impenetrability
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