Late 18th century; earliest use found in James Cobb (1756–1818), playwright. Apparently originally a nickname given to John Philpot Curran, Irish lawyer, politician, and judge, with reference to his first appearance in court, when his nervousness apparently rendered him initially unable to speak; a character of this name appears in J. O'Keeffe's opera The Son-in-Law, but it is unclear whether Curran was so-called after the character, or vice versa.