Think of it as something that's hidden away in a complex, confusing maze of ideas. It's not something you can easily grasp or explain.
Here are some examples:
* "The professor's lecture on quantum physics was abstruse, leaving most students baffled."
* "The ancient text contained abstruse symbolism that only a select few scholars could decipher."
* "The author's writing style was so abstruse that it was difficult to follow the plot."
Essentially, "abstruse" describes something that requires significant effort to understand, often due to its complexity, obscurity, or hidden meaning.