[ im-pur-vee-uhs ]
/ ɪmˈpɜr vi əs /


not permitting penetration or passage; impenetrable: The coat is impervious to rain.
incapable of being injured or impaired: impervious to wear and tear.
incapable of being influenced, persuaded, or affected: impervious to reason; impervious to another's suffering.

Nearby words

  1. impertinency,
  2. impertinent,
  3. impertinently,
  4. imperturbable,
  5. imperturbation,
  6. impetiginous,
  7. impetigo,
  8. impetigo herpetiformis,
  9. impetigo neonatorum,
  10. impetigo vulgaris

Also im·per·vi·a·ble [im-pur-vee-uh-buhl] /ɪmˈpɜr vi ə bəl/.

Origin of impervious

From the Latin word impervius, dating back to 1640–50. See im-2, pervious

Related formsim·per·vi·ous·ly, adverbim·per·vi·ous·ness, noun

Can be confusedimpermeable impervious Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for imperviousness



/ (ɪmˈpɜːvɪəs) /


not able to be penetrated, as by water, light, etc; impermeable
(often postpositive foll by to) not able to be influenced (by) or not receptive (to)impervious to argument
Derived Formsimperviously, adverbimperviousness, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for imperviousness



1640s, from Latin impervius "that cannot be passed through," from assimilated form of in- "not, opposite of" (see in- (1)) + pervius "letting things through," from per "through" + via "road." Related: Imperviously; imperviousness.

Online Etymology Dictionary, © 2010 Douglas Harper