The Chinese word **细心 (xìxīn)**, meaning "careful" or "attentive," is a compound word formed through a logical semantic combination of its two constituent characters. The first character, **细 (xì)**, carries the core meanings of "fine," "thin," or "meticulous," emphasizing detail and precision. The second character, **心 (xīn)**, means "heart" or "mind," representing the center of thought and intention. When combined, the compound literally suggests a "fine/detailed mind" or a "meticulous heart," metaphorically describing a person whose attention and intention are focused on the particulars, thereby giving rise to the abstract quality of being careful and thorough. This formation follows a common adjective-noun (or modifier-head) structure in Chinese where the first element modifies the nature of the second.