private eye a private detective. The term is first recorded in a story (1938) by Raymond Chandler. It has been suggested that the origin of the expression was the American detective agency founded by Allan Pinkerton; their motto (c.1855) was ‘We never sleep’, and the agency was informally known as ‘The Eye’.

Private Eye is the title of a British satirical magazine, founded in 1962; some of its ironical euphemisms, such as Ugandan affairs and tired and emotional, have passed into the language.

pri·vate eye • n. inf. a private investigator.