Church body upset over spirit audibly fading away (11)
I believe the answer is:
evanescence
'fading away' is the definition.
(to evanesce is to fade away or vanish)
'church body upset over spirit audibly' is the wordplay.
I cannot quite understand how this works, but
'church' could be 'ce' (abbreviation for Church of England) and 'ce' is present in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for evanescence that I've seen before include "A quick vanishing" , "Fading" , "tendency to pass rapidly" , "Transient quality" .)