im·​pen·​e·​tra·​ble | \ (ˌ)im-ˈpe-nə-trə-bəl How to pronounce impenetrable (audio) \

Definition of impenetrable

1a : incapable of being penetrated or pierced
b : inaccessible to knowledge, reason, or sympathy : impervious
2 : incapable of being comprehended : inscrutable

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Other Words from impenetrable

impenetrably \ (ˌ)im-​ˈpe-​nə-​trə-​blē How to pronounce impenetrable (audio) \ adverb

Examples of impenetrable in a Sentence

The fort's defenses were thought to be impenetrable. the ancient temple was surrounded by vast stretches of impenetrable jungle
Recent Examples on the Web Ryan’s defense has been nearly impenetrable this season. Steve Gamel Contributing Writer, Denton Record-Chronicle, "Ryan's defense tasked with slowing down Longview run game in third round," 25 Dec. 2020 But Esposito, whose near-impenetrable Fring consistently tops lists of the best villains of all time, almost didn’t get the part. Washington Post, "You’ve seen Giancarlo Esposito in everything. Now the actor wants you to see him as himself.," 18 Dec. 2020 Flanked by DeForest Buckner, the Colts have become almost impenetrable up the middle. Joel A. Erickson, The Indianapolis Star, "Insider: 38 things to watch in Colts' national showcase against Packers," 22 Nov. 2020 Though the foliage was almost impenetrable, down here the air was warm and the long underwear had been left behind. Susan Casey, Field & Stream, "F&S Classics: An Improbable Elk Hunt," 6 Dec. 2020 Even so, the Nammatj is a worthwhile investment for a truly portable, practically impenetrable double-wall tent. Adrienne Donica, Popular Mechanics, "The Best Winter Tents for Your Next Snowy Adventure," 3 Dec. 2020 Their barbs became too severe, their gossip too corrosive, the Five of Hearts too impenetrable. Dan Chiasson, The New Yorker, "What Henry Adams Understood About History’s Breaking Points," 30 Nov. 2020 Behind an seemingly impenetrable run defense and the improved play of quarterback Ian Book, the Irish have overcome an uneven start to the regular season to mold an argument for No. 1. Paul Myerberg, USA TODAY, "Where the College Football Playoff stands after Week 13," 30 Nov. 2020 The documents revealed allegations of corruption and negligence, punctured the Vatican’s reputation as one of the world’s most impenetrable institutions, and were later seen as influencing Benedict XVI’s landmark decision to step down. Washington Post, "Paolo Gabriele, Vatican butler whose leaks exposed turmoil under Pope Benedict XVI, dies at 54," 25 Nov. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'impenetrable.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of impenetrable

15th century, in the meaning defined at sense 1a

History and Etymology for impenetrable

Middle English impenetrabel, from Middle French impenetrable, from Latin impenetrabilis, from in- + penetrabilis penetrable

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Time Traveler for impenetrable

Time Traveler

The first known use of impenetrable was in the 15th century

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Statistics for impenetrable

Last Updated

7 Jan 2021

Cite this Entry

“Impenetrable.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2021.

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More Definitions for impenetrable


How to pronounce impenetrable (audio)

English Language Learners Definition of impenetrable

: impossible to pass or see through
: impossible to understand


im·​pen·​e·​tra·​ble | \ im-ˈpe-nə-trə-bəl How to pronounce impenetrable (audio) \

Kids Definition of impenetrable

1 : impossible to pass through or see through impenetrable walls impenetrable darkness
2 : impossible to understand an impenetrable mystery

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Comments on impenetrable

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