"to make fun of, to banter," 1845, American English; according to "Dictionary of American Slang," the earliest example is capitalized, hence it is probably from the familiar version of the proper name Joshua, but just which Joshua, or why, is long forgotten. Perhaps it was taken as a typical name of an old farmer. The word was in use earlier than the career of U.S. humorist Josh Billings, pseudonym of Henry Wheeler Shaw (1818-1885), who did not begin to write and lecture until 1860; but his popularity after 1869 may have influence that of the word.Related: Joshed; joshing.