Man, say, overcome by a passage in church (5)
I believe the answer is:
aisle
'passage in church' is the definition.
(passage leading to the altar in a church)
'man say overcome by a' is the wordplay.
'man say' becomes 'isle' (Isle of Man).
'overcome by' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'isle' after 'a' is 'AISLE'.
(Other definitions for aisle that I've seen before include "Way between seating areas" , "Division of the nave in church" , "Passageway between pews" , "Here comes the bride" , "Part of a church" .)