‘钻研’ is a compound verb meaning to delve deeply into a subject with great focus and persistence, often over a long period, in order to master it. The first character 钻 (zuān) literally means 'to drill' or 'to bore into', suggesting penetrating beneath the surface; the second character 研 (yán) means 'to research' or 'to study thoroughly'. Together, they evoke the image of drilling down into knowledge — not just skimming, but probing, analyzing, and refining understanding. It implies intellectual rigor, patience, and dedication.

This word is commonly used in academic, technical, or professional contexts — for example, when describing someone’s approach to learning a language, mastering a craft, or solving complex problems. It carries a positive, respectful connotation and is often applied to scholars, engineers, doctors, or artists. While it can be used reflexively (e.g., 他钻研了很久), it typically takes a direct object (e.g., 钻研数学, 钻研古籍). It is formal and written-leaning, though also common in spoken Mandarin among educated speakers.