impenetrable

[ im-pen-i-truh-buhl ]
/ ɪmˈpɛn ɪ trə bəl /

adjective

not penetrable; that cannot be penetrated, pierced, entered, etc.
inaccessible to ideas, influences, etc.
incapable of being understood; inscrutable; unfathomable: an impenetrable mystery.
Physics. possessing impenetrability.

Origin of impenetrable

1425–75; late Middle English impenetrabel < Latin impenetrābilis. See im-2, penetrable

OTHER WORDS FROM impenetrable

im·pen·e·tra·ble·ness, noun im·pen·e·tra·bly, adverb

Example sentences from the Web for impenetrable

British Dictionary definitions for impenetrable

impenetrable
/ (ɪmˈpɛnɪtrəbəl) /

adjective

incapable of being pierced through or penetrated an impenetrable forest
incapable of being understood; incomprehensible impenetrable jargon
incapable of being seen through impenetrable gloom
not susceptible to ideas, influence, etc impenetrable ignorance
physics (of a body) incapable of occupying the same space as another body

Derived forms of impenetrable

impenetrability, noun impenetrableness, noun impenetrably, adverb