Quite aloof air Lysander possesses (6)
I believe the answer is:
fairly
'quite' is the definition.
(I've seen this before)
'aloof air lysander possesses' is the wordplay.
'possesses' says the answer is hidden in the clue.
'FAIRLY' can be found hidden inside 'aloof air lysander'.
(Other definitions for fairly that I've seen before include "In an evenhanded manner - somewhat" , "pretty" , "Evenhandedly" , "Rather" , "Justly, without favouring one party" .)