Abstruse most nearly means:

• A. Dense
• B. Obscure
• C. Plain
• D. Esoteric

Answer: (D)

Understanding nuanced vocabulary: recognizing subtle shades of meaning in adjectives that describe difficulty. Abstruse describes ideas that are hard to grasp, often because they are technical, abstract, or intended for specialists. Of the options, the best fit emphasizes that specialized aspect: esoteric, which means knowledge or information meant for or understood by a small, specialized group. It carries both the sense of difficulty and a sense that ordinary readers wouldn’t readily grasp it without specific background. Dense can describe writing that is heavy or packed with information, but it doesn’t inherently imply a specialized audience. Plain is the opposite of abstruse, and obscure is close in meaning but doesn’t highlight the intended-for-a-select-audience nuance as well as esoteric does.