Unusual air and grace in deportment (8)
I believe the answer is:
carriage
'deportment' is the definition.
(both can mean someone's posture or gait)
'unusual air and grace' is the wordplay.
'unusual' indicates anagramming the letters.
'and' says to put letters next to each other.
'air' put after 'grace' is 'graceair'.
'graceair' with letters rearranged gives 'CARRIAGE'.
'in' is the link.
(Other definitions for carriage that I've seen before include "Perhaps a smoker's" , "freight charges" , "Coach - deportment" , "Drawn vehicle" , "Horse-drawn passenger vehicle" .)