Close with a lot of property? (6)
I believe the answer is:
This clue is a double definition.
'close' is the first definition.
(both can mean uncomfortably warm)
'with a lot of property?' is the second definition.
(with lots of stuff)
(Other definitions for stuffy that I've seen before include "needing to be aired" , "Airless - strait-laced" , "Close, airless" , "Close - conventional and dull" , "Airless or dull and narrow-minded" .)