Couple allowed jewellery item (8)
I believe the answer is:
bracelet
'jewellery item' is the definition.
(I've seen this before)
'couple allowed' is the wordplay.
'couple' becomes 'brace' (brace can mean a pair of something).
'allowed' becomes 'let' (to let is to allow or permit).
'brace'+'let'='BRACELET'
(Other definitions for bracelet that I've seen before include "Personal ornament" , "Let caber be made into a piece of jewellery" , "charm?" , "Bangle" , "Jewellery worn around the wrist" .)