im·​preg·​na·​ble | \im-ˈpreg-nə-bəl \

Definition of impregnable 

1 : incapable of being taken by assault : unconquerable an impregnable fortress

2 : unassailable also : impenetrable impregnable walls

Keep scrolling for more

Other Words from impregnable

impregnability \ (ˌ)im-​ˌpreg-​nə-​ˈbi-​lə-​tē \ noun
impregnableness \ im-​ˈpreg-​nə-​bəl-​nəs \ noun
impregnably \ -​blē \ adverb

Did You Know?

Since the days when the Norman French ruled England, English-speakers have been captured by the allure of French terms. Impregnable is one of the many English words that bear a French ancestry. 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.

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

Despite the assurances of pundits and pollsters that Wisconsin, which had not gone for a Republican presidential candidate since 1984, was part of Clinton’s impregnable blue wall, Donald Trump carried the state. Glenn C. Altschuler,, "'Fall of Wisconsin': Why Dems lose, and keep on losing," 13 July 2018 Even as the Zoo Tower remained impregnable, the Soviets were able to fly their flag over the Reichstag. David Grossman, Popular Mechanics, "The Fearsome Nazi Tower That Held Off the Allies in Berlin," 11 June 2018 Following the occupation of Angkor by the Chams from 1177 to 1181, the new king decided to build an impregnable fortress at the heart of his empire. Antonia Neubauer, Town & Country, "How to Plan a Trip to Asia," 5 Oct. 2016 Gabrielle Union as a desperate mother hellbent on saving her two children being held in an impregnable home. Kevin Crust,, "L.A. movie openings, May 11," 6 May 2018 And yet everywhere there is impregnable defiance—and aspiration. Rachel Aviv, The New Yorker, "Deana Lawson’s Kingdom of Restored Glory," 8 Jan. 2018 Matt Murray was impregnable in the first contest, but the Flyers broke down his defenses often in the second one. Tim Hackett,, "Stanley Cup Playoffs Roundup: Flyers Rebound, Jets Soar, Haula a Hero," 14 Apr. 2018 This is the one venue in sports that remains virtually impregnable to boorish behavior. Paul Daugherty,, "Doc on Masters 2018: 'Dilly-dilly' elsewhere – the beauty is in the civility at Augusta," 4 Apr. 2018 The Conservative Party enjoys impregnable majorities in places like Hampshire East, but has recently lost metropolitan beachheads such as Kensington and Battersea. The Economist, "BagehotBritain now has a four-party system," 30 Sep. 2017

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

See More

First Known Use of impregnable

15th century, in the meaning defined at sense 1

History and Etymology for impregnable

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

Keep scrolling for more

Learn More about impregnable

Share impregnable

Listen to Our Podcast about impregnable

Dictionary Entries near impregnable








Statistics for impregnable

Look-up Popularity

Time Traveler for impregnable

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

See more words from the same century

Keep scrolling for more

More Definitions for impregnable



English Language Learners Definition of impregnable

: not able to be captured by attack : very strong

: not likely to be weakened or changed


im·​preg·​na·​ble | \im-ˈpreg-nə-bəl \

Kids Definition of impregnable

: not able to be captured by attack : unconquerable

Keep scrolling for more

Comments on impregnable

What made you want to look up impregnable? Please tell us where you read or heard it (including the quote, if possible).


to clear from alleged fault or guilt

Get Word of the Day daily email!

Test Your Vocabulary

Difficult Vocab Quiz

  • the-education-of-achilles-eugne-delacroix
  • Which is a synonym of discomfit?
True or False

Test your knowledge - and maybe learn something along the way.

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!