Wind instrument brought back from Borneo boxed well (4)
I believe the answer is:
oboe
'wind instrument' is the definition.
(oboe is a kind of wind instrument)
'back from borneo boxed well' is the wordplay.
'back' shows that the letters should be reversed in order.
'from' says the answer is hidden in the clue.
'eobo' can be found hidden inside 'borneo boxed well'.
'eobo' backwards is 'OBOE'.
'brought' acts as a link.
(Other definitions for oboe that I've seen before include "Slender double-reed instrument" , "Double-reed woodwind" , "Reed instrument" , "Double-reeded woodwind instrument" , "Musical instrument" .)