A service returned from a distance (4)
I believe the answer is:
afar
'from a distance' is the definition.
(I've seen this before)
'a service returned' is the wordplay.
'service' becomes 'raf' (Royal Air Force).
'returned' is a reversal indicator.
'raf' written backwards gives 'far'.
'a'+'far'='AFAR'
(Other definitions for afar that I've seen before include "Inhabitant of Ethiopia" , "from baseline to baseline?" , "(From/at) a great distance" , "Distant, not near" , "long way back" .)