Definition from Wiktionary, the free dictionary
- unaffected or unable to be affected by
- The man was completely impervious to the deception we were trying.
- preventative of any penetration; impenetrable, impermeable, particularly of water
- Although patchworked and sagging, the roof proved impervious to the weather.
- immune to damage or effect
- The old car seemed to be impervious to the wear and tear of age.
Derived terms 
unaffected or unable to be affected by
preventative of any penetration; impenetrable, impermeable