noun
abstruseness; difficulty to understand
Refers to something being hard to comprehend, often used for obscure words or concepts. The word itself is somewhat literary and not common in everyday speech.
この文章は難義で、何を言いたいのかわからない。
This passage is abstruse; I can't tell what it's trying to say.
彼の説明は難義を極めた。
His explanation was extremely abstruse.