transitive verb.
To mar or spoil the appearance or surface of; disfigure.
transitive verb.
To impair the usefulness, value, or influence of.
transitive verb.
To obliterate; destroy.
The Century Dictionary and Cyclopedia
To mar the face or surface of; disfigure; spoil the appearance of: as, to deface a monument.
To impair or efface; blot or blot out; erase; obliterate; cancel: as, to deface an inscription; to deface a record.
the GNU version of the Collaborative International Dictionary of English
transitive verb.
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