Impermeable \Im*per"me*a*ble\, a. [Pref. im- not + permeable:
cf. F. imperm['e]able, 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. -- {Im*per"me*a*ble*ness},
n. -- {Im*per"me*a*bly}, adv.