Im*per"me*a*ble (?), a. [Pref. im- not + permeable: cf. F. imperm'eable, L. impermeabilis.]
Not permeable; not permitting passage, as of a fluid. through its substance; impervious; impenetrable; as, India rubber is impermeable to water and to air.
, n. -- Im*per"me*a*bly
© Webster 1913.