im·​per·​vi·​ous | \(ˌ)im-ˈpər-vē-əs \

Definition of impervious 

1a : not allowing entrance or passage : impenetrable a coat impervious to rain

b : not capable of being damaged or harmed a carpet impervious to rough treatment

2 : not capable of being affected or disturbed impervious to criticism

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Other Words from impervious

imperviously adverb
imperviousness noun

Synonyms & Antonyms for impervious


impenetrable, impermeable, tight


penetrable, permeable, pervious

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Did You Know?

The English language is far from impervious, and, of course, a great many Latinate terms have entered it throughout its history. Impervious is one of the many that broke through in the 17th century. It comes from the Latin impervius, which adds the prefix im- to pervius, meaning "passable" or "penetrable." Pervius-which is also the source of the relatively uncommon English word pervious, meaning "accessible" or "permeable"-comes from per-, meaning "through," and via, meaning "way."

Examples of impervious in a Sentence

He looked at her, impervious to her tears … — Jean Stafford, Children Are Bored on Sunday, (1945) 1953 … the trunk … is encased in so hard a bark, as to be almost impervious to a bullet … — Herman Melville, Omoo, 1847 … Berlin struck me, above all, as impervious to any political reactions whatever … — Stephen Spender, New York Times Magazine, 30 Oct.1977 the material for this coat is supposed to be impervious to rain the rain forest is impervious to all but the most dedicated explorers
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Recent Examples on the Web

After being mostly impervious this year to jitters over a trade war, technology stocks have recently also been hit. Gunjan Banerji, WSJ, "Investors Seek Protection From Market’s Biggest Winners," 2 July 2018 But real-estate development contributes to the problem because impervious surfaces, such as driveways and rooftops, replace the grasses and vegetation that naturally filter out waste swept up in storm water. Lara Korte, WSJ, "Developers Go With the Flow as New Water Rules Kick In," 10 July 2018 All around the Warriors are the fruits and roots of their winning culture—the work, the attitude, the impervious chill. Rob Mahoney,, "Facing a Harsh Free-Agency Reality, DeMarcus Cousins Embraces the Absurd," 3 July 2018 Oh, to be not like the swimmer, but like that lake: deep and impervious and with room for us all. Lauren Markham, Longreads, "For Me, With Love and Squalor," 7 June 2018 The storage facility is highly secured, and the casks are impervious to weather and risk of attack. Wayne Perry,, "Oldest US nuke plant, near Jersey shore, closing Sept. 17," 2 July 2018 For many years, the Lower East Side appeared impervious to the gentrification sweeping many Manhattan neighborhoods. New York Times, "Offered $54 Million for Air Rights, Co-op Says ‘No Thanks’," 14 June 2018 The joke may still be on Xi, however, as many Chinese users already access HBO shows through VPNs, which are impervious to the censorship. Natasha Bach, Fortune, "John Oliver Mocked President Xi Jinping. Now His Show—And All of HBO—Are Blocked In China," 25 June 2018 Their minds are impervious to Maeve's (Thandie Newton) takeover attempts and Ashley Stubbs' (Luke Hemsworth) voice commands. Sandra Upson, WIRED, "Westworld Recap, Season 2 Episode 9: The Many Lives of the Man in Black," 18 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'impervious.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of impervious

1640, in the meaning defined at sense 1a

History and Etymology for impervious

Latin impervius, from in- + pervius pervious

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The first known use of impervious was in 1640

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More Definitions for impervious



English Language Learners Definition of impervious

: not allowing something (such as water or light) to enter or pass through

: not bothered or affected by something


im·​per·​vi·​ous | \im-ˈpər-vē-əs \

Kids Definition of impervious

1 : not letting something enter or pass through The coat is impervious to rain.

2 : not bothered or affected by something He's impervious to their criticism.


im·​per·​vi·​ous | \(ˈ)im-ˈpər-vē-əs \

Medical Definition of impervious 

: not allowing entrance or passage medication packaged in a container impervious to air and light

Other Words from impervious

imperviousness noun

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Comments on impervious

What made you want to look up impervious? Please tell us where you read or heard it (including the quote, if possible).


to make faulty or ineffective

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