Couple rented item of jewellery (8)
I believe the answer is:
bracelet
'item of jewellery' is the definition.
(I've seen this before)
'couple rented' is the wordplay.
'couple' becomes 'brace' ('brace' can be a synonym of 'couple'**).
'rented' becomes 'let' (I've seen this before).
'brace'+'let'='BRACELET'
(Other definitions for bracelet that I've seen before include "Ornamental band worn on wrist" , "Arm jewellery" , "Jewellery worn around the wrist" , "Bangle" , "Might Bel react badly to this jewellery?" .)