carapace

Definitions

1. A hard protective covering of bone or chitin, especially one which covers the dorsal portion of an animal.
2. That which protects.
   figuratively

Equivalents

Examples

“So, little by little, youth loosens the hard carapace of confining custom their elders have⟳ built over the human heart.”

“This is all a massive failure of science to pierce the carapace of public ignorance.”

CEFR level