Type of loose grey coat (8)
I believe the answer is:
category
'type' is the definition.
(I've seen this before)
'loose grey coat' is the wordplay.
'loose' indicates anagramming the letters (letters are loosened from their original positions).
'grey'+'coat'='greycoat'
'greycoat' anagrammed gives 'CATEGORY'.
'of' is the link.
(Other definitions for category that I've seen before include "Coy Greta found among this class of things" , "Type" , "Class or division of similar subjects" , "Class with the same attribute" , "Classification of grey-coat" .)