Word Origin & History
goof1916, Amer.Eng., "stupid person," perhaps a variant of Eng. dial. goff "foolish clown" (1869), from 16c. goffe, probably from M.Fr. goffe "awkward, stupid," of uncertain origin. Or Eng. goffe may be from M.E. goffen "speak in a frivolous manner," possibly from O.E. gegaf "buffoonery," and gaffetung "scolding."
Sense of "a blunder" is c.1954, probably infl. by gaffe. The verbal meaning "waste time" is 1932; the verb meaning "make a mistake" is from 1941. Goof off "loaf" is also from 1941. Adj. goofy is attested from 1921. The Disney character of that name began life as Dippy Dawg c.1929. Goofball "narcotic" is from 1938; as an intensive of goof, it dates from 1959.