impermeable
Americanadjective
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not permeable; impassable.
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Chemistry, Geology. (of porous substances, rocks, etc.) not permitting the passage of a fluid through the pores, interstices, etc.
adjective
Other Word Forms
Etymology
Origin of impermeable
From the Late Latin word impermeābilis, dating back to 1690–1700. See im- 2, permeable
Compare meaning
How does impermeable compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
If you have a waterproof raincoat, you could say that your coat is impermeable to the rain. Something that is impermeable does not allow water or liquid to pass through it. Made up of the prefix im-, meaning “not,” and the adjective permeable, meaning “allowing to pass through,” impermeable is used in much the same way as impervious or impenetrable. However, more so than these words, impermeable is especially associated with liquids and is often used in a scientific or technical context. Some gadgets, like waterproof watches and underwater cameras, are designed to be impermeable.
Vocabulary lists containing impermeable
"Simon's Saga," Vocabulary from Episode 32
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Challenge, List 12
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Girl, Interrupted
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
State officials estimated the costs at $4,100 per acre of paved or impermeable surface for those that decide to help fund local stormwater projects, and said the costs for other options could be considerably higher.
From Los Angeles Times ● Jul. 29, 2026
"We come to live in bubbles, impermeable to one another," he said.
From BBC ● Apr. 17, 2026
“Europe needs to make itself impermeable to every interference” by outside powers, whether the U.S. or Russia, he said.
From The Wall Street Journal ● Jan. 19, 2026
Previous studies have suggested that a layer of impermeable rock at the top of the descending tectonic plate serves as a sealed lid, trapping fluid in the pores of underlying rock layers.
From Science Daily ● May 7, 2024
They tie nkisis of leaves around their wrists and declare themselves impermeable to bullets, immune to death.
From "The Poisonwood Bible" by Barbara Kingsolver
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
