im·​preg·​na·​ble im-ˈpreg-nə-bəl How to pronounce impregnable (audio)
: incapable of being taken by assault : unconquerable
an impregnable fortress
: unassailable
also : impenetrable
impregnable walls
impregnability noun
impregnableness noun
impregnably adverb

Did you know?

Impregnable is one of the many English words that bear a French ancestry, thanks to the Norman conquest of England in 1066. It derives from the Middle French verb prendre, which means "to take or capture." Combining prendre with various prefixes has given our language many other words, too, including surprise, reprise, and enterprise. Remarkably, impregnable has a different origin from the similar-looking word pregnant; that word comes from a different Latin word, praegnas, meaning "carrying a fetus."

Examples of impregnable in a Sentence

an impregnable fortress that had foiled one invader after another over the centuries the castle's supposedly impregnable walls
Recent Examples on the Web Once when told that a certain French fortress was impregnable and once when told that his mother-in-law had died. Andrew Stuttaford, National Review, 25 Mar. 2024 Inflation is a currency phenomenon, which means that Summers et al are floating non sequiturs rooted in the absurd notion that the U.S. economy is an impregnable island of economic activity, as opposed to an interconnected part of a global whole. John Tamny, Forbes, 25 Feb. 2024 Some Wall Street analysts agree with Belloni and his tweet that the fact Netflix’s competitors license content to it is a sign of its impregnable position atop the streaming heap. Paolo Confino, Fortune, 7 Jan. 2024 The monster acts with the implacable, impregnable logic of a natural disaster. Robert Rubsam, New York Times, 4 Jan. 2024 Not long ago, apparently, the Supreme Intelligence got smacked down by Captain Marvel (Brie Larson), which suggests that A.I. is not impregnable. Anthony Lane, The New Yorker, 15 Dec. 2023 Outside Yellowknife, the fires had jumped first one impregnable firebreak, then another and then another. David Wallace-Wells, New York Times, 24 Oct. 2023 This, for many hours after the Hamas attack began through multiple breaches in the supposedly impregnable multimillion-dollar Israeli fence around Gaza, was the sum of the state’s presence in the area: some 30 police officers recruited by the festival organizers to provide security. Roger Cohen Avishag Shaar-Yashuv, New York Times, 15 Oct. 2023 Hitler's combat engineers have given evidence that the impregnable fort of yesterday is today just another target for superior offensive weapons. Ashraya Gupta, Scientific American, 7 Sep. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'impregnable.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English imprenable, from Middle French, from in- + prenable vulnerable to capture, from prendre to take — more at prize

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of impregnable was in the 15th century


Dictionary Entries Near impregnable

Cite this Entry

“Impregnable.” Dictionary, Merriam-Webster, Accessed 15 Jun. 2024.

Kids Definition


im·​preg·​na·​ble im-ˈpreg-nə-bəl How to pronounce impregnable (audio)
: not able to be captured by assault : unconquerable
an impregnable fortress
impregnably adverb

More from Merriam-Webster on impregnable

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