Greek garret (5)
I believe the answer is:
attic
I believe this clue is a double definition.
'greek' is the first definition.
(from ancient Athens or Attica)
'garret' is the second definition.
(synonyms)
(Other definitions for attic that I've seen before include "Room inside a building's roof space" , "Top chamber" , "room with lots of junk?" , "Top level" , "Upstairs room" .)