[ɪmˈpɛnɪtrəbl], (Adjective)

Definitions:
- impossible to pass through or enter
(e.g: a dark, impenetrable forest)

- impossible to understand
(e.g: her expression was impenetrable)


Phrases:

Origin:
late Middle English: via French from Latin impenetrabilis, from in- ‘not’ + penetrabilis ‘able to be pierced’, from the verb penetrare (see penetrate)