Synonyms: impenetrability, impenetrableness
Definition: incomprehensibility by virtue of being too dense to understand
Similar words: incomprehensibility
Definition: the quality of being incomprehensible
Synonyms: impenetrability, imperviousness
Definition: the quality of being impenetrable (by people or light or missiles etc.)
Similar words: quality
Definition: an essential and distinguishing attribute of something or someone
Usage: the quality of mercy is not strained--Shakespeare