look down one's nose at, to

To regard or treat someone with disdain. One writer suggests that this term comes from a customary attitude of disapproval shown by lowering the eyelids and looking downward, thereby focusing on one’s own nose. This explanation does not jibe with the body language involved in turn up one’s nose, yet both expressions involve contempt or disdain, and indeed, to look down on has meant expressing contempt from about 1700; nose was added about 1900. “He went in to look down his nose at them—it might give him some faint satisfaction,” wrote John Galsworthy (To Let, 1921).