To make a (verbal) blunder. This term dates from the early eighteenth century and presumably was analogous to stepping where one should not. Jonathan Swift used it in Polite Conversation (1738), “The bishop has put his foot in it,” and a century later the term was defined in a book on slang (1823). Putting one’s foot in one’s mouth is of more recent provenance; it merited a definition in P. W. Joyce’s English As We Speak It (1910): “To a person who habitually uses unfortunate blundering expressions: ‘You never open your mouth but you put your foot in it.’” Today it is sometimes referred to as foot-in-mouth disease.