Something inflationary, in a manner (3)
I believe the answer is:
air
'manner' is the definition.
(air can mean someone's manner or character)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for air that I've seen before include "Short song" , "Mixture of gases, especially oxygen" , "Gas mix surrounding the earth" , "Divulge" , "Ventilate a tune?" .)