Not all unbelief is heresy for Archbishop of Canterbury (6)
I believe the answer is:
fisher
'archbishop of canterbury' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'not all unbelief is heresy' is the wordplay.
'not all' indicates a hidden word (only some of the letters).
'FISHER' is hidden within 'unbelief is heresy'.
'for' is the link.
Can you help me to learn more?
(Other definitions for fisher that I've seen before include "UK shipping forecast area" , "Marten; angler" , "One who angles" , "Jeremy - (Beatrix Potter)" .)