風馬牛不相及 [ㄈㄥ ㄇㄚˇ ㄋㄧㄡˊ ㄅㄨˋ ㄒㄧㄤ ㄐㄧˊ; feng1 ma3 niu2 bu4 xiang1 ji2] to be completely unrelated to one another (idiom) irrelevant ◄ ►