Dump wicked, spiteful woman (3-5)
I believe the answer is:
she-devil
'spiteful woman' is the definition.
(I've seen this before)
'dump wicked' is the wordplay.
'dump' becomes 'she'd' (I've seen this in another clue).
'wicked' becomes 'evil' (synonyms).
'shed'+'evil'='SHE-DEVIL'
(Other definitions for she-devil that I've seen before include "woman like Lilith" , "Malicious and spiteful woman" .)