Knight, embraced by niece, getting disordered item of apparel (7)
I believe the answer is:
necktie
'item of apparel' is the definition.
'knight embraced by niece getting disordered' is the wordplay.
'knight' becomes 'kt'.
'embraced by' indicates putting letters inside.
'getting disordered' indicates anagramming the letters.
'niece' with letters rearranged gives 'necie'.
'kt' inserted into 'necie' is 'NECKTIE'.
(Other definitions for necktie that I've seen before include "Ascot?" , "Knotted garment (US)" , "Strip of fabric often worn by men" , "Fashion accessory - cite Ken (anag)" , "Item worn round collar (mainly US)" .)