"fool, simpleton," 1855, of unknown origin, apparently from the surname and perhaps influenced by slang mug "dupe, fool" (1851; see mug (n.2)). It also was the name of simple card game (1855) and the word each player tried to call out before the other in the game when two cards matched. The name turns up frequently in humor magazines, "comic almanacks," etc. in 1840s and 1850s.