noun
sexual liaison; intimate encounter
Classical Chinese-derived yojijukugo referring to a romantic or sexual meeting, often with a poetic or euphemistic tone. Rare in modern Japanese; found mainly in literary or historical contexts.
「雲雨巫山」は、男女の密会を表す故事成語として知られる。
雲雨巫山 is known as a classical idiom expressing a secret meeting between a man and a woman.
From a Chinese legend in which King Huai of Chu dreamed of a goddess at Mount Wu (巫山) who shared his bed and departed with the words 'I am the cloud in the morning and the rain in the evening.' The phrase came to symbolize a romantic or sexual encounter.