(1):

(v. t.) To destroy or mar the face or external appearance of; to disfigure; to injure, spoil, or mar, by effacing or obliterating important features or portions of; as, to deface a monument; to deface an edifice; to deface writing; to deface a note, deed, or bond; to deface a record.

(2):

(v. t.) To destroy; to make null.