impenetrably

/ɪmˈpɛnɪtrəbli/
adverb
  1. In a way that cannot be entered, passed through, or understood.
    • The fortress walls were impenetrably thick, keeping all invaders out.
    • The ancient text was impenetrably complex, baffling even the experts.
    • The forest was impenetrably dark, with no light reaching the ground.
Antonyms
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