Mur·phy’s law /ˌmɜːfiz ˈlɔː $ ˌmɜːrfiz ˈlɒː/ noun [uncountableU] informal especially American EnglishAmE RFa tendency for bad things to happen whenever it is possible for them to do so – used humorously 墨菲定律〔一种认为凡有可能出差错的事终将出差错的论断;幽默用法〕 SYN British English sod’s law