Definition of impregnable in US English:



  • 1(of a fortified position) unable to be captured or broken into.

    ‘an impregnable wall of solid sandstone’
    figurative ‘the companies are impregnable to takeovers’
    • ‘In the middle of Hue, however, was a virtually impregnable fortress known as the Citadel, with towers, ramparts, moats, concrete walls, and bunkers.’
    • ‘In their accounts of hunting for a way out, they provide a survey of a border territory, an impregnable zone through which the people imprisoned above would never pass.’
    • ‘But sometime during the final week your impregnable fortress crashes and burns, but you land on your feet at the very end of the month.’
    • ‘Incredibly sturdy, it had been built to serve as a nuclear bomb shelter if necessary, supposedly an impregnable fortress of civil defense.’
    • ‘On 15 September French and Serbian mountain troops successfully attacked hitherto impregnable Bulgarian positions.’
    • ‘Labyrinthine streets of ancient slum housing traversed the steep hill up to the impregnable city walls.’
    • ‘But he had other things in mind - plans that had been consuming his soul since he had escaped from La Fortaleza, the once impregnable fortress that had fallen a little over a year ago.’
    • ‘No doubt it will go the way of all seemingly impregnable empires of the past.’
    • ‘Later, he began building model castles, surrounded by fortified emplacements, and he spent hours studying the virtually impregnable fortifications of Vauban.’
    • ‘There has to be something; no fortress is completely impregnable.’
    • ‘Yes sir, but we think that the position is impregnable and we can hold it against far superior forces.’
    • ‘Austria ruled directly only in the newly formed Kingdom of Lombardy-Venetia, but from the impregnable fortresses of the Quadrilateral in the central Po Valley Austrian bayonets could reach any part of Italy.’
    • ‘The key to the Belgian defence along the Albert Canal was the supposedly impregnable fortress of Eben-Emael.’
    • ‘Singapore, an island at the southern end of the Malay Peninsula, was considered a vital part of the British Empire and supposedly impregnable as a fortress.’
    • ‘Between them they created a seemingly impregnable fortress, naturally protected on three sides by cliffs and defended by concentric lines of mutually supporting fortifications.’
    • ‘I'm satisfied this place is nearly impregnable.’
    • ‘In the face of these pressures, Anglican natural theology retreated into the apparently impregnable fortress of biology.’
    • ‘The walls surrounding the city were impregnable, never before breached by an attacking army.’
    • ‘The castle had been built with a good eye for defense; this place was virtually impregnable.’
    • ‘However, instead of building the fort on a hill, the impassable wetlands were used to create an impregnable site, the biggest marshland in England.’
    invulnerable, impenetrable, unattackable, unassailable, inviolable, secure, strong, stout, safe, well fortified, well defended
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    1. 1.1 Unable to be defeated or destroyed; unassailable.
      ‘the case against Hastings would have been almost impregnable’
      • ‘But Preston were knocked sideways by the shock of seeing their impregnable lead suddenly wiped out.’
      • ‘He's seen what looked like an impregnable 22-point lead slashed to just two ahead of me.’
      • ‘He required forceful persuasion to forego county commitments to fly back for the final, but no-one smiled brighter after the previously impregnable Ireland had been clinically defeated by 47 runs.’
      • ‘After all, within the space of a three-month election campaign she managed to squander a seemingly impregnable lead of 22 percent over the SPD.’
      • ‘The victory stretched their 100 percent winning sequence to 19 matches and they now have an impregnable nine point lead at the top.’
      • ‘He was impregnable, unbeatable, and nothing, no creature could even come close to conquering the mighty Kong.’
      • ‘Still, to perfect one's play at Worms, you will have to spend a lot of time learning the nuances of each weapon and tricks on how to defeat what seems like an impregnable AI.’
      • ‘Then, without warning, you've got the world's number one goalkeeper in self-destruct mode, the England captain glancing an own goal home and a seemingly impregnable lead overturned.’
      unassailable, unbeatable, undefeatable, unshakeable, invincible, indomitable, unconquerable, unstoppable, invulnerable
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Late Middle English: from Old French imprenable, from in- ‘not’ + prendre ‘take’ (from Latin prehendere). The current spelling arose in the 16th century, perhaps influenced by Old French variants.