impervious

adjective

im·​per·​vi·​ous (ˌ)im-ˈpər-vē-əs 

1

a

: 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

imperviously adverb

imperviousness noun

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."

Synonyms

• impenetrable
• impermeable
• tight

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

Recent Examples on the Web

This was somewhat fortuitous as the new Soviet T-34 tanks acquired by Ho Chi Minh and the Viet Minh were impervious to the M20 Recoilless Rifle and the Vespa TAP would not have fared well in the jungles of Vietnam. —Mike Hanlon, New Atlas, 12 Oct. 2024

In South America, China, Russia, and Iran are providing military, economic, and diplomatic support to Nicolás Maduro’s authoritarian government in Venezuela, reinforcing his conviction that his regime is impervious to pressure. —Antony J. Blinken, Foreign Affairs, 1 Oct. 2024

Waterproof materials are impervious to water, providing a complete barrier, while water-resistant materials only resist water penetration to a certain degree before the water seeps through. —Sophie Flaxman, Better Homes & Gardens, 26 Sep. 2024

In a few instances, these colonies were impervious to more than one antimicrobial drug. —Lauren Leffer, Popular Science, 11 Sep. 2024

Word History

Etymology

Latin impervius, from in- + pervius pervious

First Known Use

1615, in the meaning defined at sense 1a

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Kids Definition

impervious

adjective

im·​per·​vi·​ous (ˈ)im-ˈpər-vē-əs 

1

: not letting something enter or pass through

a coat impervious to rain

2

: not disturbed or upset

impervious to criticism

imperviousness noun

Medical Definition

impervious

adjective

im·​per·​vi·​ous (ˈ)im-ˈpər-vē-əs 

: not allowing entrance or passage

medication packaged in a container impervious to air and light

imperviousness noun