Spades sever rabbit's tail (4)
I believe the answer is:
scut
'rabbit's tail' is the definition.
(scut can mean a rabbit's tail)
'spades sever' is the wordplay.
'spades' becomes 's' (abbreviation in card games).
'sever' becomes 'cut' (I've seen this before).
's'+'cut'='SCUT'
(Other definitions for scut that I've seen before include "Cuts into a small tail" , "Reindeer tail" , "Short tail of hare" , "(Hare's) short upright tail" , "Short erect tail" .)