Uninteresting apartment (4)
I believe the answer is:
flat
This clue is a double definition.
'uninteresting' is the first definition.
(thesaurus)
'apartment' is the second definition.
(synonyms)
(Other definitions for flat that I've seen before include "Prostrate" , "place to live" , "Uninteresting - piece of scenery" , "character on the staff" , "Apartment; plane" .)