Title adopted by popular churchman (8)
I believe the answer is:
minister
'churchman' is the definition.
(I know that minister is a type of clergyman)
'title adopted by popular' is the wordplay.
I cannot quite see how this works, but
'popular' could be 'in' ('in' can mean trendy) and 'in' is found in the answer.
'title' could be 'mister' and 'mister' is found within the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for minister that I've seen before include "Head of a government department" , "Parson" , "Member of parliament" , "Clergyman - government member" , "Merit sin (anag.)" .)