Jewellery item getting endless scrutiny (4)
I believe the answer is:
stud
'jewellery item' is the definition.
(I've seen this before)
'endless scrutiny' is the wordplay.
'endless' means to remove the last letter.
'scrutiny' becomes 'study' (study is a kind of scrutiny).
'study' with its last letter taken away is 'STUD'.
'getting' is the link.
(Other definitions for stud that I've seen before include "Sexual athlete" , "Collar fastener - form of poker" , "Macho - stables - boss" , "Horse-breeding place" , "Form of poker game" .)