Belt making bonier lad look silly (9)
I believe the answer is:
bandolier
'belt' is the definition.
(bandolier is a kind of belt)
'bonier lad look silly' is the wordplay.
'look silly' indicates an anagram (I've seen this in other clues).
'bonier'+'lad'='bonierlad'
'bonierlad' is an anagram of 'BANDOLIER'.
'making' acts as a link.
(Other definitions for bandolier that I've seen before include "Round belt" , "Ammunition belt" , "Gun cartridge belt" , "Shoulder belt for carrying bullets" , "Shoulder belt for cartridges" .)