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Synonyms

impenetrable

American  
[im-pen-i-truh-buhl] / ɪmˈpɛn ɪ trə bəl /

adjective

  1. not penetrable; that cannot be penetrated, pierced, entered, etc.

  2. inaccessible to ideas, influences, etc.

  3. incapable of being understood; inscrutable; unfathomable.

    an impenetrable mystery.

    Synonyms:
    hidden, obscure, mysterious, incomprehensible
    Antonyms:
    lucid, clear
  4. Physics. possessing impenetrability.


impenetrable British  
/ ɪmˈpɛnɪtrəbəl /

adjective

  1. incapable of being pierced through or penetrated

    an impenetrable forest

  2. incapable of being understood; incomprehensible

    impenetrable jargon

  3. incapable of being seen through

    impenetrable gloom

  4. not susceptible to ideas, influence, etc

    impenetrable ignorance

  5. physics (of a body) incapable of occupying the same space as another body

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of impenetrable

1425–75; late Middle English impenetrabel < Latin impenetrābilis. See im- 2, penetrable

Explanation

Impenetrable describes something that's impossible to get through. Whether it's a brick wall or a difficult reading passage, something impenetrable won't let you in. Impenetrable comes from the Latin impenetrabilis, meaning "not to put or get into, enter into." Impenetrable, the adjective, has two meanings. When you're trying to learn a subject that is so complicated, so confusing or so detailed that it seems like it's in another language or from another planet, it's impenetrable — like calculus. Or a physical object can be impenetrable, meaning it is impossible to actually enter or get inside of, like that impenetrable nightclub that has bouncers watching every entrance to keep you and your friends out.

Keep Reading on Vocabulary.com

Vocabulary lists containing impenetrable

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.

ReWilding Argentina is providing logistical support to the effort, which some conservationists hope will open the door to translocating guanacos even farther north, to Argentina’s Impenetrable National Park.

From Science Magazine • Nov. 1, 2023

One in the Virunga Forest, which straddles the borders between Uganda, Rwanda and the Democratic Republic of the Congo, the other in the Bwindi Impenetrable Forest in Uganda.

From BBC • Jun. 19, 2022

There’s a soulful gorilla undisturbed by visitors in Bwindi Impenetrable National Park in Uganda.

From New York Times • Oct. 29, 2021

Impenetrable as it may be to many an alienated, confounded moviegoer — Lo, an 88% Rotten Tomatoes rating!

From Los Angeles Times • Aug. 7, 2021

Impenetrable clouds are thundering unceasingly, And all the world is full of rain: Kānta is a stone, and Love is cruel, A rain of arrows pierces me.

From Vidy?pati: Bang?ya pad?bali; songs of the love of R?dh? and Krishna by Vidy?pati Th?kura