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Synonyms

impregnable

1 American  
[im-preg-nuh-buhl] / ɪmˈprɛg nə bəl /

adjective

  1. strong enough to resist or withstand attack; not to be taken by force, unconquerable.

    an impregnable fort.

    Synonyms:
    invulnerable
    Antonyms:
    vulnerable
  2. not to be overcome or overthrown.

    an impregnable argument.

    Synonyms:
    unassailable

impregnable 2 American  
[im-preg-nuh-buhl] / ɪmˈprɛg nə bəl /

adjective

  1. susceptible to impregnation, as an egg.


impregnable 1 British  
/ ɪmˈprɛɡnəbəl /

adjective

  1. unable to be broken into or taken by force

    an impregnable castle

  2. unable to be shaken or overcome

    impregnable self-confidence

  3. incapable of being refuted

    an impregnable argument

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

impregnable 2 British  
/ ˌɪmprɛɡˈneɪtəbəl, ɪmˈprɛɡnəbəl /

adjective

  1. able to be impregnated; fertile

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See invincible.

Other Word Forms

Etymology

Origin of impregnable1

First recorded in 1400–50; late Middle English impregnable, imprenable, from Middle French, equivalent to im- im- 2 + prenable pregnable

Origin of impregnable2

impregn(ate) + -able

Explanation

When something is impregnable it is not easily taken by force and can stand up to any attack. We usually use it in reference to some form of protection, like a fort or a solid defensive line in football. The genealogy of the adjective impregnable includes the Middle French word prenable, meaning "vulnerable, easily conquered," which itself came from the verb prendre, which meant "to take." The addition of the negative prefix im- flipped the meaning. Impregnable can be used to describe anything that cannot be entered or successfully attacked. Seventeenth-century theater critic Jeremy Collier once said, "True courage is a result of reasoning. A brave mind is always impregnable."

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

"Impregnable" Pantelleria, Benito Mussolini's Gibraltar in what he once called Mare Nostrum, was doomed.

From Time Magazine Archive

Of chambers as the cedars— Impregnable of eye; And for an everlasting roof The gables of the sky.

From Time Magazine Archive

Impregnable England At Madison Square Garden, Manhattan, Johnny Shugrue bumped his nose on Pal Moran's fist in the first round of their prospective twelve.

From Time Magazine Archive

In 1896 appeared ‘The Impregnable Rock of Holy Scripture,’ revised and enlarged from Good Words. 

From The Real Gladstone an Anecdotal Biography by Ritchie, J. Ewing (James Ewing)

Impregnable Malta surrenders without a shot; his most reckless schemes are crowned with success.

From War and Peace by Tolstoy, Leo, graf

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