Synonym: dense, impassable, inaccessible, obscure, unapproachable, unclear, unintelligible, vague. Similar words: penetrate, penetrating, venerable, impeccable, impermeable, imperturbable, unimpeachable, transferable. Meaning: [ɪm'penɪtrəbl] 
adj. 1. not admitting of penetration or passage into or through 2. permitting little if any light to pass through because of denseness of matter 3. impossible to understand.
adj. 1. not admitting of penetration or passage into or through 2. permitting little if any light to pass through because of denseness of matter 3. impossible to understand. 
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91) What sort of life went on beyond the impenetrable lines of the Red irregulars.
92) To know that what is impenetrable to us really exists ... is at the center of true religiousness .
93) The SSL VPN should be built on a solid platform that is impenetrable to hackers at the Operating System level, the networking protocol level, and the application level.
94) The sun is high above the impenetrable shade of my wood.
95) She was the picture of a serene and exquisite but impenetrable sphinx.
More similar words: penetrate, penetrating, venerable, impeccable, impermeable, imperturbable, unimpeachable, transferable, impending, impenitent, arable, parable, honorable, wearable, bearable, adorable, incurable, admirable, tolerable, separable, comparable, endurable, memorable, favourable, favorable, desirable, execrable, miserable, imperceptible, vulnerable.