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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

  • impenetrability noun
  • impenetrableness noun
  • impenetrably adverb

Etymology

Origin of impenetrable

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

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.

His eyes were an intense, unblinking blue: vividly alive in that impenetrable face.

From Literature

Her eyes met mine, and in them was something steely and impenetrable and daring.

From Literature

The disclosures at funds like this often are as impenetrable as they are voluminous.

From The Wall Street Journal

Unai Emery's side are being questioned after winning two of their past six Premier League games, and falling to three home defeats in five matches at the once impenetrable Villa Park.

From BBC

“An impenetrable wall of disinfectant for your face.”

From Literature

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.