The word "志愿" is formed as a compound of two meaningful characters: "志" (zhì), which conveys one’s will, aspiration, or determined purpose, and "愿" (yuàn), which means a wish, desire, or heartfelt inclination. Together, they semantically merge to express the concept of a "voluntary will" or a "conscious aspiration"—an action or commitment driven not by obligation but by personal resolve and earnest desire. This formation reflects a classical Chinese linguistic pattern where two synonyms or near-synonyms combine to create a nuanced, abstract noun that emphasizes both the internal resolve ("志") and the earnest longing ("愿") behind a choice, such as in the modern terms "志愿者" (volunteer) or "志愿军" (volunteer army).