impregnable

adjective

im·​preg·​na·​ble im-ˈpreg-nə-bəl 

1

: incapable of being taken by assault : unconquerable

an impregnable fortress

2

: unassailable

also : impenetrable

impregnable walls

impregnability

(ˌ)im-ˌpreg-nə-ˈbi-lə-tē 

noun

impregnableness

im-ˈpreg-nə-bəl-nəs 

noun

impregnably

im-ˈpreg-nə-blē 

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."

Synonyms

• bulletproof
• indomitable
• insuperable
• insurmountable
• invincible
• invulnerable
• unbeatable
• unconquerable
• unstoppable

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

Superstar Harmanpreet Kaur's unbelievable 171 not out that destroyed an impregnable Australia in a remarkable semi-final upset was seen as a turning point. —Tristan Lavalette, Forbes, 15 Oct. 2024

But their defenses are not impregnable. —David Zipper, Vox, 7 Dec. 2018

From Sandro Tonali to Dan Burn and Dubravka, this current side have been borderline impregnable over the past month. —Chris Waugh, The Athletic, 16 Jan. 2025

For more than half a century, the Assad dynasty appeared to have an impregnable hold over Syria. —Natasha Hall, Foreign Affairs, 9 Dec. 2024

Word History

Etymology

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

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Kids Definition

impregnable

adjective

im·​preg·​na·​ble im-ˈpreg-nə-bəl 

: not able to be captured by assault : unconquerable

an impregnable fortress

impregnably

-blē 

adverb