Distinctive atmosphere (4)
I believe the answer is:
aura
'distinctive atmosphere' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for aura that I've seen before include "Intangible essence emanating from a person" , "Distinctive quality around a person or place" , "'Air, atmosphere (4)'" , "Intangible something around a person" , "Nimbus" .)