Cup fraction (5)
I believe the answer is:
ounce
'cup fraction' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ounce that I've seen before include "Small quantity - snow leopard" , "One sixteenth of a pound" , "Carnivore" , "Fraction of a pound" , "Panther, perhaps" .)