Head back into church, uplifted by key spirit (7)
I believe the answer is:
essence
'spirit' is the definition.
(essence can mean something's spirit or heart)
'head back into church uplifted by key' is the wordplay.
I cannot really see how this works, but
'church' could be 'ce' (Church of England) and 'ce' is found within the answer.
'key' could be 'e' (musical key) and 'e' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for essence that I've seen before include "Intrinsic nature; four Dn" , "Perfume or distillation" , "quality of perfume?" , "Scent; core" , "Perfume or concentrated extract" .)