Close-fitting necklace (6)
I believe the answer is:
choker
'close-fitting necklace' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for choker that I've seen before include "A high stiff collar or tight-fitting necklace" , "Close-fitting band round neck" , "Close-fitting necklace" , "Band worn around the neck" , "Tight necklet - sportsman that wilts under pressure" .)