The word 外遇 is formed by combining two characters to create a vivid conceptual metaphor. The first character, 外 (wài), means "outside" or "external", establishing a spatial boundary, such as outside a marriage or a committed relationship. The second character, 遇 (yù), means "to meet" or "an encounter". When placed together, the term literally paints a picture of an "external meeting" or an "encounter from the outside", directly and metaphorically describing a romantic or sexual liaison that exists beyond the acknowledged boundaries of one's primary relationship.