from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Impossible to permeate: an impermeable membrane; an impermeable border.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. impossible to permeate
- adj. not allowing passage, especially of liquids; waterproof
from the GNU version of the Collaborative International Dictionary of English
- adj. Not permeable; not permitting passage, as of a fluid. through its substance; impervious; impenetrable.
from The Century Dictionary and Cyclopedia
- Not permeable; not permitting the passage of a fluid (especially water) through its substance.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. preventing especially liquids to pass or diffuse through
From Latin impermeābilis, from im- + permeābilis ("permeable"). (Wiktionary)