Correct, unfortunately, about headless cleric (6)
I believe the answer is:
rector
'cleric' is the definition.
(I've seen this before)
'correct unfortunately about headless' is the wordplay.
I cannot quite see how this works, but
'about' could be 're' (common abbreviation for 'with reference to') and 're' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for rector that I've seen before include "Church official" , "Cleric" , "Parish priest" , "Preacher Man" , "Churchman" .)