Little boy (6)
I believe the answer is:
nipper
'little boy' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for nipper that I've seen before include "Claw (large) - child (small)" , "It may pinch" , "Small boy (old slang)" , "Kid - claw" , "Small child or crab's claw" .)