/ ɪmˈpɜːviəs; NAmE -ˈpɜːrv-/ adjective
1.
impervious to sth not affected or influenced by sth :
impervious to criticism / pain
2.
impervious (to sth) ( technical ) not allowing a liquid or gas to pass through :
an impervious rock / layer
impervious to moisture
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WORD ORIGIN
mid 17th cent.: from Latin impervius (from in- not + pervius permeable) + -ous .