Order sort of grey coat (8)
I believe the answer is:
category
'order' is the definition.
(thesaurus)
'sort of grey coat' is the wordplay.
'sort of' indicates anagramming the letters.
'grey'+'coat'='greycoat'
'greycoat' anagrammed gives 'CATEGORY'.
(Other definitions for category that I've seen before include "Genre" , "Group of classified items" , "Coy Greta found among this class of things" , "Class or order" , "Type" .)