Main Entry: im·per·me·able

Pronunciation: \(ˌ)im-ˈpər-mē-ə-bəl\

Function: adjective

Etymology: Late Latin impermeabilis, from Latin in- + Late Latin permeabilis permeable

Date: 1697

: not permitting passage (as of a fluid) through its substance; broadly : impervious

— im·per·me·abil·i·ty \-ˌpər-mē-ə-ˈbi-lə-tē\ noun