Lose road-kill! (6)
I believe the answer is:
mislay
'lose' is the definition.
('mislay' can be a synonym of 'lose')
'road-kill' is the wordplay.
'road' becomes 'mi'.
'kill' becomes 'slay' (slaying is a kind of killing).
'mi'+'slay'='MISLAY'
(Other definitions for mislay that I've seen before include "Temporarily not find" , "Put something aside and forget where" , "Be unable to find" , "Put in wrong place, lose temporarily" , "Lose (an item)" .)