More angry about Church beginning to roast witch (8)
I believe the answer is:
sorcerer
'witch' is the definition.
(thesaurus)
'more angry about church beginning to roast' is the wordplay.
'more angry' becomes 'sorer' ('sore' can be similar in meaning to 'angry').
'about' indicates putting letters inside.
'church' becomes 'ce' (abbreviation for Church of England).
'beginning to' suggests taking the first letters.
The initial letter of 'roast' is 'r'.
'ce'+'r'='cer'
'sorer' enclosing 'cer' is 'SORCERER'.
(Other definitions for sorcerer that I've seen before include "Magician with musical apprentice" , "Male magician, wizard" , "In stories, he has magical powers that he uses to harm others" , "Necromancer or wizard" , "Potter, say" .)