Darling spirit (5)
I believe the answer is:
angel
I believe this is a double definition.
'darling' is the first definition.
(I've seen this in another clue)
'spirit' is the second definition.
(Other definitions for angel that I've seen before include "One backing theatre production" , "One usually obliging" , "Heavenly messenger" , "darling!" , "One backing plays" .)