Idle l-lout (4)
I believe the answer is:
loaf
'idle' is the definition.
(loafing is a kind of idling)
'l-lout' is the wordplay.
'lout' becomes 'oaf' ('oaf' can be a synonym of 'lout').
'l'+'oaf'='LOAF'
(Other definitions for loaf that I've seen before include "bloomer, perhaps" , "BRINK/BRICK" , "Bread - brain!" , "Idle - head" , "Idle - moulded lump of bread" .)