The phrase "晴空万里" is formed by directly combining the two-character term "晴空", meaning "clear sky", where "晴" (clear) modifies "空" (sky), with the two-character term "万里", meaning "ten thousand li", where "万" (ten thousand) quantifies "里" (a traditional unit of distance) to express vastness. The combination results in a four-character idiom where "万里" serves as a hyperbolic intensifier for "晴空", literally depicting a clear sky stretching across an immense distance.