Murphy's Law

noun

1. the facetious proposition that if something can go wrong, it will.

Murphy's law

noun

1. informal.
   another term for Sod's law

Murphy's Law

1. A rule that states, “If something can go wrong, it will.” An addition to this law reads, “and usually at the worst time.” The identity of “Murphy” is unknown, but the saying was first used during the 1940s and may have originated with members of the armed forces in World War II .

Word History and Origins

Origin of Murphy's Law¹

An Americanism dating to 1950–55; named after Edward A. Murphy, Jr., (1918–90), an American aerospace engineer who worked on safety systems

Word History and Origins

Origin of Murphy's Law¹

C20: of uncertain origin

Idioms and Phrases

If anything can go wrong, it will, as in We may think we've covered all the details for the benefit, but remember Murphy's law . The identity of Murphy, if ever a real person, is unknown. Some think it alludes to (but was not invented by) a feckless Irishman named Murphy. [c. 1940]