difficult to understand; abstruse; unintelligible
Describes texts, concepts, or explanations that are hard to comprehend due to complexity or obscurity. Often used for academic, technical, or philosophical content.
This paper is abstruse; no matter how many times I read it, I can't understand it.
His explanation was too difficult to follow, and no one could keep up.
This paper is full of technical terms and hard to understand.
The content of this philosophy book is hard to understand.
His theory is extremely abstruse, so even experts struggle to understand it.