Fun a cleric can maybe rely on (7)
I believe the answer is:
revelry
'fun' is the definition.
(thesaurus)
'a cleric can maybe rely on' is the wordplay.
'a cleric can' becomes 'rev' (I can't justify this - if you can you should believe this answer much more).
'maybe' indicates anagramming the letters.
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'rely' is an anagram of 'elry'.
'rev' put into 'elry' is 'REVELRY'.
Can you help me to learn more?
(Other definitions for revelry that I've seen before include "Riotous feasting" , "Merrymaking" , "Merriment" , "Noisy celebration" , "Feasting, noisy festivities" .)