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

Two years ago, the U.S. Centers for Disease Control began tracking a sharp rise in cases of extensively drug-resistant (XDR) shigellosis — infections by particular strains of Shigella bacteria that are impervious to most antibiotics. —Corinne Purtill, Los Angeles Times, 18 Dec. 2024

Surface water flooding is especially dangerous for cities with a high proportion of impervious soil coverage and hard surfaces—such as roads and parking lots—that prevent rainwater from being absorbed, increasing the likelihood and impact of flooding. —Natalie Donback, TIME, 18 Dec. 2024

The road project itself would mean more stormwater runoff because of additional impervious surfaces, but Wayne said the tunnel project is expected to reduce the stormwater discharge to the combined sewage system by 82%. —Eric D. Lawrence, Detroit Free Press, 7 Nov. 2024

Antimicrobial resistance is increasing humanity’s risk of being confronted with pathogens impervious to lifesaving medical tools, undermining the effectiveness of antibiotics and HIV, TB and malaria treatments and jeopardizing billions of lives. —Peter Sands, Forbes, 20 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