Things ending on balcony, close (6)
I believe the answer is:
stuffy
'close' is the definition.
(both can mean uncomfortably warm)
'things ending on balcony' is the wordplay.
'things' becomes 'stuff' (I've seen this before).
'ending on' suggests the final letters.
The last letter of 'balcony' is 'y'.
'stuff'+'y'='STUFFY'
(Other definitions for stuffy that I've seen before include "Close - conventional and dull" , "Old-fashioned" , "needing to be aired" , "Airless - strait-laced" , "Badly ventilated" .)