adj.
Pronunciation: ( ˌ )im- ' pe-n ə -tr ə -b ə l
Function: adjective
Etymology: Middle English impenetrabel, from Middle French impenetrable, from Latin impenetrabilis, from in- + penetrabilis penetrable
Date: 15th century
1 a : incapable of being penetrated or pierced b : inaccessible to knowledge, reason, or sympathy : IMPERVIOUS
2 : incapable of being comprehended : INSCRUTABLE
– im · pen · e · tra · bly \ -bl ē \ adverb