Im-pĕr'vi-oŭs, a.

[Prefix im, not, and pervious; Lat. impervius, It. & Sp. impervio.] Not pervious; not admitting of entrance or passage through; as, cloth impervious to water. “This gulf impassable, impervious.” Milton.

Synonyms—Impassable; pathless; impenetrable; imperviable.