Animal run over (4)
I believe the answer is:
wolf
'animal' is the definition.
(I have seen 'Predatory animal' mean 'wolf' so perhaps 'animal' could also mean 'wolf')
'run over' is the wordplay.
'run' becomes 'flow' (synonyms).
'over' says the letters should be written in reverse.
'flow' backwards is 'WOLF'.
(Other definitions for wolf that I've seen before include "Austrian composer" , "Lupine mammal" , "Pack animal; composer" , "Dog-like animal - womaniser" , "Predator that hunts in packs" .)