Lad clutching top of designer group (4)
I believe the answer is:
body
'group' is the definition.
(body can mean an organisation or group)
'lad clutching top of designer' is the wordplay.
'lad' becomes 'boy' (I've seen this in another clue).
'clutching' means one lot of letters goes inside another.
'top of' indicates taking the first letters.
The first letter of 'designer' is 'd'.
'boy' enclosing 'd' is 'BODY'.
(Other definitions for body that I've seen before include "Corpse; full quality of wine" , "Substance" , "Physique" , "Physical structure of an organism" , "Carcase" .)