n. [ Cf. F. impénétrabilité. ] 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 ]
n. [ Cf. F. pénétrabilité. ] The quality of being penetrable; susceptibility of being penetrated, entered, or pierced. Cheyne. [ 1913 Webster ]