adj.
Impossible to permeate: an impermeable membrane; an impermeable border.
impermeability im·per'me·a·bil'i·ty or im·per'me·a·ble·ness n.
impermeably im·per'me·a·bly adv.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
