[ 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.
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 forms

im·per·vi·ous·ly, adverbim·per·vi·ous·ness, noun

Can be confused

impermeable 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 Forms

imperviously, 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