The word "碰面" is formed by combining two distinct concepts into a single, vivid action. The first character, "碰" (pèng), carries the core idea of a casual, often unplanned touching or bumping into something. The second character, "面" (miàn), literally means "face" but is used here metaphorically to represent the presence or person of someone. Therefore, the formation visually and conceptually blends the notion of an informal, coincidental encounter ("碰") with the direct, personal facing of another individual ("面"), resulting in the meaning "to meet up" or "to run into someone", inherently suggesting a casual and often unforeseen meeting.