Affected manners; ventilates (4)
I believe the answer is:
airs
This clue is a double definition.
'affected manners' is the first definition.
(I've seen this before)
'ventilates' is the second definition.
('air' can be a synonym of 'ventilate')
(Other definitions for airs that I've seen before include "- - and graces" , "Affected manners" , "songs" , "Affectedness" , "Melodies or artificial manners" .)