This is how higher education got starved and how government became impenetrable.
From the sfgate.com
It represents all that is impenetrable about who people are and what they think.
From the time.com
The lasagna's cheesy top turns into a nearly impenetrable crust when it travels.
From the denverpost.com
However, as effective as these measures are, no security system is impenetrable.
From the washingtonpost.com
Everywhere else the roads were mere tracks which were impenetrable to artillery.
From the en.wikipedia.org
Thank goodness it's not impenetrable balderdash, then, says fan Nicholas Lezard.
From the guardian.co.uk
The Wranglers were impenetrable during the three games inside the Orleans Arena.
From the orlandosentinel.com
Blacks are impenetrable, colors pop out at you, and viewing angles are supreme.
From the forbes.com
In their current agglomerated state, too many firms are impenetrable black boxes.
From the bloomberg.com
More examples
Not admitting of penetration or passage into or through; "an impenetrable fortress"; "impenetrable rain forests"
Dense: permitting little if any light to pass through because of denseness of matter; "dense smoke"; "heavy fog"; "impenetrable gloom"
Impossible to understand; "impenetrable jargon"
(impenetrableness) impenetrability: incomprehensibility by virtue of being too dense to understand
In metaphysics, impenetrability is the name given to that quality of matter whereby two bodies cannot occupy the same space at the same time. ...
Not penetrable; incomprehensible; inscrutable
Inaccessible. See Phase Impenetrability Condition.
Term applied historically to the area of the dry chaco with the most inhospitable conditions for white settlement, due to lack of water; the name of a zone of northwestern Chaco Province.