Refectory’s a shambles (4)
I believe the answer is:
mess
I believe this clue is a double definition.
'refectory's' is the first definition.
(thesaurus)
'a shambles' is the second definition.
(thesaurus)
(Other definitions for mess that I've seen before include "Disorderly state" , "Where military personnel eat" , "Canteen - chaos" , "Military canteen" , "Meal" .)