Encourage young lad to nick uniform (4)
I believe the answer is:
buoy
'encourage young' is the definition.
I can't tell whether this definition defines the answer.
'lad to nick uniform' is the wordplay.
I cannot really understand how this works, but
'uniform' could be 'u' (phonetic alphabet: alpha, bravo, charlie etc.) and 'u' is present in the answer.
'lad' could be 'boy' (lad means a young boy) and 'boy' is found within the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for buoy that I've seen before include "Floating item often marking a hazard" , "Marine float" , "Floating sea marker" , "Warning floater" , "keep from going under" .)