im·pen·e·tra·ble /(ˌ)ɪmˈpɛnətrəbəl/
 (a.)不能穿過的,不可理喻的,費解的,頑固的
 Im·pen·e·tra·ble a.
 1. Incapable of being penetrated or pierced; not admitting the passage of other bodies; not to be entered; impervious; as, an impenetrable shield.
 Highest woods impenetrable
 To star or sunlight.   --Milton.
 2. Physics Having the property of preventing any other substance from occupying the same space at the same time.
 3. Inaccessible, as to knowledge, reason, sympathy, etc.; unimpressible; not to be moved by arguments or motives; as, an impenetrable mind, or heart.
    They will be credulous in all affairs of life, but impenetrable by a sermon of the gospel.   --Jer. Taylor.
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 impenetrable
      adj 1: not admitting of penetration or passage into or through; "an
             impenetrable fortress"; "impenetrable rain forests"
             [ant: penetrable]
      2: permitting little if any light to pass through because of
         denseness of matter; "dense smoke"; "heavy fog";
         "impenetrable gloom" [syn: dense, heavy]
      3: impossible to understand; "impenetrable jargon"