im ‧ per ‧ vi ‧ ous /ɪmˈpɜːviəs $ -ɜːr-/ BrE AmE adjective [not before noun]
[ Date: 1600-1700 ; Language: Latin ; Origin: impervius , from pervius 'allowing things to pass through' , from per 'through' + via 'way' ]
1 . formal not affected or influenced by something and seeming not to notice it
impervious to
His ego was impervious to self-doubt.
2 . technical not allowing anything to enter or pass through:
impervious volcanic rock
impervious to
materials that are impervious to water