Part of a buck (6)
I believe the answer is:
antler
'part of a buck' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for antler that I've seen before include "Branched animal horn" , "One seen on stag" , "Reindeer horn" , "part of Rudolph" , "Horn maybe of 24" .)