impenetrable
US /ɪmˈpen.ə.trə.bəl/
UK /ɪmˈpen.ə.trə.bəl/

1.
impenetrable, inaccesible
impossible to pass through or enter
:
•
The fortress had an impenetrable defense system.
La fortaleza tenía un sistema de defensa impenetrable.
•
The dense jungle was almost impenetrable.
La densa selva era casi impenetrable.
2.
incomprensible, indescifrable
impossible to understand; incomprehensible
:
•
His handwriting was almost impenetrable.
Su letra era casi impenetrable.
•
The philosopher's theories were often impenetrable to the average person.
Las teorías del filósofo eran a menudo impenetrables para la persona promedio.