Exile concerned with stale atmosphere vacated enclosure (7)
I believe the answer is:
refugee
'exile' is the definition.
(I know that refugee is a type of exile)
'concerned with stale atmosphere vacated enclosure' is the wordplay.
'concerned with' becomes 're' (re can mean regarding or about).
'stale atmosphere' becomes 'fug' (fug is a kind of atmosphere. I am not sure about the 'stale' bit.).
'vacated' means to remove the middle letters (internal letters vacate the word).
'enclosure' with its centre taken out is 'ee'.
're'+'fug'+'ee'='REFUGEE'
Can you help me to learn more?
(Other definitions for refugee that I've seen before include "One fleeing disaster" , "One who seeks asylum abroad" , "One fleeing troubles" , "War-forced migrant" , "Asylum seeker" .)