abstrusity
n. C2 Proficiency ab·strusi·ty
n. the quality of being very difficult to understand. You use this to describe things that are so complex or strange they are hard to explain.
n. the quality of being obscure, difficult to understand, or difficult to explain. Often used to describe abstract or highly technical subjects.
The professor's lecture was full of abstrusity.
The legal documents were so full of abstrusity that even the lawyers had to consult a dictionary.
The philosopher's later works are often dismissed for their abstrusity, though they contain profound insights into the nature of human consciousness.
From abstruse + -ity.