Spiteful woman's wrongful act (3)
I believe the answer is:
cat
'spiteful woman's' is the definition.
(I've seen this in another clue)
'wrongful act' is the wordplay.
'wrongful' indicates anagramming the letters (I've seen this in other clues).
'act' anagrammed gives 'CAT'.
(Other definitions for cat that I've seen before include "See 23" , "A tom" , "See 21" , "eg Leopard" , "An old whip with nine tails" .)