Disfigures (7)
'disfigures' is the definition.
(defacing is a kind of disfiguring)
This is the entire clue.
'disfigures' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mars that I've seen before include "world" , "Roman war god; planet" , "Spoils - planet" , "Famous Texas mission" , "March to the French" .)