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

Such a war would be motivated, in China, by a politics of identity that is largely impervious to economic rationality and other strategic considerations. —Rana Mitter, Foreign Affairs, 22 Apr. 2025

For years, decades even, that faux feline impervious to the rain was my secret excuse. —Domenico Starnone, New Yorker, 20 Apr. 2025

The 27-year-old was impervious under pressure and at one stage chopped the ball past one of Frankfurt’s forwards on the outside of his own box. —Jay Harris, New York Times, 11 Apr. 2025

The fabrics used for the outers are not impervious to rain, but water ingress is slowed through the use of (Nikwax) chemical treatments. —Carlton Reid, Forbes.com, 10 Apr. 2025

Word History

Etymology

Latin impervius, from in- + pervius pervious

First Known Use

1615, in the meaning defined at sense 1a

Rhymes for impervious

• pervious

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