Attacker finding assistant protected by senior cleric (6)
I believe the answer is:
raider
'attacker' is the definition.
(I've seen this before)
'assistant protected by senior cleric' is the wordplay.
'assistant' becomes 'aide' (aide is a kind of assistant).
'protected by' means one lot of letters goes inside another.
'senior cleric' becomes 'rr' (I can't explain this - if you can you should believe this answer much more).
'aide' inserted into 'rr' is 'RAIDER'.
'finding' acts as a link.
Can you help me to learn more?
(Other definitions for raider that I've seen before include "looter" , "person who's involved in sacking?" , "person taking food from larder" , "One making a rapid surprise attack" , "Viking" .)