Not easily penetrated. The property of a material or soil that des not allow, or allows only with great difficulty, the movement or passage of water.
IMPERMEABLE (IM-PURR-ME-UH-BULL)
Meaning of IMPERMEABLE (IM-PURR-ME-UH-BULL) in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012