Church shamefaced about black magic (7)
I believe the answer is:
sorcery
'black magic' is the definition.
(synonyms)
'church shamefaced about' is the wordplay.
'church' becomes 'CE' (abbreviation for Church of England).
'shamefaced' becomes 'sorry' (I can't explain this - if you can you should give a lot more credence to this answer).
'about' means one lot of letters goes inside another.
'ce' put inside 'sorry' is 'SORCERY'.
Can you help me to learn more?
(Other definitions for sorcery that I've seen before include "practice being aligned with the devil?" , "occultism" , "Trickery" , "devilish practices" , "Use of magic" .)