Very short, my youngsters (4)
I believe the answer is:
lads
'youngsters' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for lads that I've seen before include "Fellows, blokes" , "Boys, young fellows" , "Youngsters" , "Fellows, chaps" , "Young men" .)