Mark with graffiti (3)
(Other definitions for tag that I've seen before include "Tie-on label" , "Name" , "Refrain" , "Label - children's game" , "Tab" .)
(Other definitions for deface that I've seen before include "six notes?" , "Spoil or damage the surface of" , "ruin" , "Spoil the surface of as with graffiti" , "blemish" .)