impregnable

/ɪmˈprɛɡnəbəl/
adjective
  1. Impossible to capture or enter by force; very strongly defended.
    • The castle was built on a hill and considered impregnable.
    • Modern cybersecurity aims to make networks as impregnable as possible.
    • The army failed to breach the city's impregnable walls.
  2. Not capable of being defeated or overcome; unshakable.
    • The team's defense was impregnable, and they won every game.
    • He had an impregnable alibi that no one could disprove.
    • Her confidence in her abilities seemed impregnable.
What does "impregnable" mean? | whatsthatwordmean | whatsthatwordmean