1540s, ridyculouse, from Latin ridiculosus "laughable," from ridiculus "that which excites laughter," from ridere "to laugh." Shakespeare and other 17c. writers sometimes spelled it rediculous. Slang extensions to "outrageous" (1839); "excellent" (1959, jazz slang). Related: Ridiculously; ridiculousness.[ridiculous etymology, ridiculous origin, 英语词源]