Female depressed about habitual seducer (4)
I believe the answer is:
wolf
'habitual seducer' is the definition.
(wolf can mean a seductive person)
'female depressed about' is the wordplay.
'female' becomes 'f' (abbreviation).
'depressed' becomes 'low' (synonyms).
'about' shows that the letters should be reversed in order.
'f'+'low'='flow'
'flow' backwards is 'WOLF'.
(Other definitions for wolf that I've seen before include "character of Prokofiev's music" , "Carnivore -- breed of 13 down" , "Pack-hunting animal" , "Predator that hunts in packs" , "SECOND PART OF 14" .)