Crooner has left some jewellery (5)
I believe the answer is:
bling
'jewellery' is the definition.
(informal term for jewellery)
'crooner has left some' is the wordplay.
'crooner' becomes 'Bing' (Bing Crosby).
'has' indicates putting letters inside.
'some' suggests taking the first letters.
The initial letter of 'left' is 'l'.
'bing' enclosing 'l' is 'BLING'.
(Other definitions for bling that I've seen before include "Showy jewellery" , "Flashy, ostentatious jewellery" , "Jazzy" , "Showy jewels etc" , "glitzy jewellery" .)