Witchcraft is unfortunate outside church (7)
I believe the answer is:
sorcery
'witchcraft' is the definition.
(I've seen this before)
'unfortunate outside church' is the wordplay.
'unfortunate' becomes 'sorry' (I've seen this in another clue).
'outside' indicates putting letters inside (some letters go outside others).
'church' becomes 'ce' (abbreviation for Church of England).
'sorry' placed around 'ce' is 'SORCERY'.
'is' is the link.
(Other definitions for sorcery that I've seen before include "practice being aligned with the devil?" , "devilish practices" , "Use of magic" , "Black magic" , "spells etc?" .)