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
The multiple attacks could be a major victory for the jihadis in a city seen as impregnable, despite attackers often targeting troops and villages on the outskirts of the city.
—
Haruna Umar, Los Angeles Times, 17 Mar. 2026
The multiple attacks could be seen as a major victory for the jihadis in a city seen as impregnable despite the jihadis often targeting troops and villages on the outskirts of the city.
—ABC News, 16 Mar. 2026
Already fairly impregnable, the Oscars for years has been protected in public view and behind the scenes by a series of federal, regional and local law enforcement groups and departments working in coordination under the auspices of the LAPD.
—Dominic Patten, Deadline, 11 Mar. 2026
Even with plentiful supplies, U.S. air-defense systems are not impregnable.
—Missy Ryan, The Atlantic, 3 Mar. 2026
See All Example Sentences for impregnable
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Haruna Umar, Los Angeles Times, 17 Mar. 2026
The multiple attacks could be seen as a major victory for the jihadis in a city seen as impregnable despite the jihadis often targeting troops and villages on the outskirts of the city.
—ABC News, 16 Mar. 2026
Already fairly impregnable, the Oscars for years has been protected in public view and behind the scenes by a series of federal, regional and local law enforcement groups and departments working in coordination under the auspices of the LAPD.
—Dominic Patten, Deadline, 11 Mar. 2026
Even with plentiful supplies, U.S. air-defense systems are not impregnable.
—Missy Ryan, The Atlantic, 3 Mar. 2026
See All Example Sentences for impregnable
Cite this Entry
“Impregnable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/impregnable. Accessed 30 Mar. 2026.
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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