from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Incapable of being penetrated: a material impervious to water.
- adj. Incapable of being affected: impervious to fear.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. unaffected or unable to be affected by
- adj. preventative of any penetration; impenetrable, impermeable, particularly of water
- adj. immune to damage or effect
from the GNU version of the Collaborative International Dictionary of English
- adj. Not pervious; not admitting of entrance or passage through.
from The Century Dictionary and Cyclopedia
- Not pervious; not to be passed through or penetrated; impermeable; impenetrable: as, a substance impervious to moisture.
- Synonyms Impenetrable, impassable, pathless.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. not admitting of passage or capable of being affected
From Latin impervius : in-, not; see in-1 + pervius, pervious; see pervious.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin impervius ("cannot be passed through"), from in- ("not") + pervius ("letting things through") (Wiktionary)