Fastens round the neck (4)
I believe the answer is:
ties
'fastens' is the definition.
(tying is a kind of fastening)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for ties that I've seen before include "Drawn games" , "Links" , "allegiances" , "Attaches, knots" , "Items of neckwear" .)