[adjective] - impossible to enter or go through, or (figurative) impossible to understandThe prison lies behind a high impenetrable wall.Outside the house the fog was thick and impenetrable (= impossible to see through because it was so thick).(figurative) The latest record contains some of their most impenetrable lyrics yet.
IMPENETRABLE
Meaning of IMPENETRABLE in English
Cambridge English vocab. Кембриджский английский словарь. 2012