One who speaks above his level of knowledge, experience or expertise. From Latin Ultra=above & beyond + crepis-idis=sole,keel.
The story goes that when the famous Greek painter Apellis made a full-body painting of Alexander the Great and showed it to the audience, a shoemaker approached him and made some comments about the rendering of the sandals of the great warrior. The painter promptly acknowledged the error and with a stroke of his brush corrected it. But after a while the same man started to comment about the robe of Alexander and the painter cut him short by saying, "Stick to the sandals, my valuable friend".
by John Prezanis July 21, 2003