The word 失踪 is formed by combining two characters: 失, which means "to lose" or "to miss", and 踪, which means "trace" or "trail". Together, they create a vivid conceptual image of "losing one's trace", where the first character indicates the action of loss and the second character specifies what is lost, not a person directly, but their trail or evidence of their presence. This formation visually and metaphorically conveys the idea of a disappearance as the vanishing of all traces, like footprints that have been erased.