Nice and neat 50% cutback for skittles (8)
I believe the answer is:
ninepins
'skittles' is the definition.
('ninepin' can be a synonym of 'skittle')
I don't understand how the remainder of the clue works.
(Other definitions for ninepins that I've seen before include "Form of skittles" , "Bowling targets" , "Skittles (IX, not V)" , "Bowling game" , "Skittles, IX objects to be knocked down" .)