Impervious

[Sarah]

Not pervious; not admitting of entrance or passage through; as,a substance impervious to water or air.This gulf impassable, impervious. Milton.The minds of these zealots were absolutely impervious. Macaulay.

[Sarah]

[im-pur-vee-uhs]
not permitting penetration or passage; impenetrable, incapable of being injured or impaired:

[Sarah]

When applied to girls: the quality of being unaware of - or otherwise unaffected by - blatant perving.

[Kit]

not allowing liquid to go through: