[goof] n [prob. alter. of E dial. goff (simpleton)] (1915) 1: a silly or stupid person
2: blunder
[2]goof vi (1932) 1 a: to spend time idly or foolishly--usu. used with off b: to engage in playful activity--usu. used with around
2: to make a usu. foolish or careless mistake: blunder--often used with up ~ vt: to make a mess of: bungle--usu. used with up -- goof on slang: to make fun of: kid, put on "you're goofing on me, right?"