To change or alter the form of; convert into a new form or shape.Specifically To mar the natural form or shape of; put out of shape; disfigure, as by malformation of a limb or some other part of the body.To render ugly, ungraceful, or displeasing; mar the beauty of; spoil: as, to deform the person by unbecoming dress; to deform the character by vicious conduct.Disfigured; being of an unnatural, distorted, or disproportioned form; displeasing to the eye.To form; fashion; delineate; engrave.In geometry, to bend without stretching or tearing.