Fellow has gone to bed with a cleric (8)
I believe the answer is:
chaplain
'a cleric' is the definition.
(I've seen this in another clue)
'fellow has gone' is the wordplay.
'fellow' becomes 'chap' (both can mean a man).
'has gone' becomes 'lain' (I can't explain this - if you can you should believe this answer much more).
'chap'+'lain'='CHAPLAIN'
'to bed with' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for chaplain that I've seen before include "Clergyman attached to an organisation" , "Clergyman attached to military unit" , "Armed services clergyman" , "Member of clergy ministering to an organisation" , "Clergyman attached to an institution, such as the army" .)