early 15c., diformyte, "condition of being deformed; physical malformation or distortion," especially "disproportionate or unnatural development of a part or parts," from Old French deformité "deformity, disfigurement" (Modern French difformité), from Latin deformitatem (nominative deformitas) "ugliness, hideousness, deformity," from deformis "misformed, misshapen," from deformare "put out of shape, disfigure," from de (see de-) + formare "to shape, fashion, build," also figurative, from forma "form, contour, figure, shape" (see form (n.)).