Spoil drive back (3)
I believe the answer is:
mar
'spoil' is the definition.
(synonyms)
'drive back' is the wordplay.
'drive' becomes 'ram' (RAM drive on a computer).
'back' is a reversal indicator.
'ram' in reverse letter order is 'MAR'.
(Other definitions for mar that I've seen before include "Oh dear!" , "Spoil something" , "Spoil, damage" , "Spoil or deface" , "Spoil stuff" .)