Youngster, nipper (5)
I believe the answer is:
sprog
I believe this clue is a double definition.
'youngster' is the first definition.
(I know that sprog is a type of youngster)
'nipper' is the second definition.
(I know that sprog is a type of nipper)
(Other definitions for sprog that I've seen before include "Child; recruit (mil. slang)" , "Infant" , "Child, colloquially" , "Kid" , "little one" .)