Couple hire item of jewellery (8)
I believe the answer is:
bracelet
'item of jewellery' is the definition.
(I've seen this before)
'couple hire' is the wordplay.
'couple' becomes 'brace' ('brace' can be a synonym of 'couple'**).
'hire' becomes 'let' (I've seen this in other clues).
'brace'+'let'='BRACELET'
(Other definitions for bracelet that I've seen before include "Let caber be made into a piece of jewellery" , "Personal ornament" , "Might Bel react to the piece of jewellery?" , "Item of jewellery on wrist" , "Item of jewellery found in Crete lab" .)