impregnable
adjective
im·preg·na·ble
im-ˈpreg-nə-bəl 
1
: incapable of being taken by assault : unconquerable
an impregnable fortress
2
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
Needless to say, Superman regains his identity in time for a final assault on a supposedly impregnable computer designed by Pryor and manned by Vaughn and his formidable sister (Annie Ross), and hidden away somewhere in the Grand Canyon.
—
Arthur Knight, HollywoodReporter, 7 July 2025
As a result, homeowners and developers are reconsidering their approach to luxury living, emphasizing fire-resistant materials, impregnable landscaping, and cutting-edge smart-home technologies.
—Abby Montanez, Robb Report, 6 July 2025
Japanese airpower destroyed supposedly impregnable British battle cruisers in the Pacific at the outset of World War II.
—Michael C. Horowitz, Foreign Affairs, 4 July 2025
Something technical would surely have been appropriate: Which programming language is most vulnerable, which most impregnable?
—Literary Hub, 1 July 2025
See All Example Sentences for impregnable
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Arthur Knight, HollywoodReporter, 7 July 2025
As a result, homeowners and developers are reconsidering their approach to luxury living, emphasizing fire-resistant materials, impregnable landscaping, and cutting-edge smart-home technologies.
—Abby Montanez, Robb Report, 6 July 2025
Japanese airpower destroyed supposedly impregnable British battle cruisers in the Pacific at the outset of World War II.
—Michael C. Horowitz, Foreign Affairs, 4 July 2025
Something technical would surely have been appropriate: Which programming language is most vulnerable, which most impregnable?
—Literary Hub, 1 July 2025
See All Example Sentences for impregnable
Cite this Entry
“Impregnable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/impregnable. Accessed 21 Jul. 2025.
Copy CitationKids Definition
impregnable
adjective
im·preg·na·ble
im-ˈpreg-nə-bəl
: not able to be captured by assault : unconquerable
an impregnable fortress
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