The word 碰巧 is formed by combining the character 碰, which conveys the idea of an unexpected encounter or "bumping into" something, with 巧, which denotes coincidence, fortuitousness, or timeliness. Together, these characters merge to create a compound that conceptually represents an event occurring by chance, as if one stumbles upon a fortunate or opportune moment, encapsulating the notion of serendipity or accidental occurrence.