Possibly lies under a part of the church (5)
I believe the answer is:
aisle
'part of the church' is the definition.
'aisle' can be an answer for 'part' (I have seen 'Part of church ' mean 'aisle' so perhaps 'part' could also mean 'aisle'). I am unsure of the 'of the church' bit.
'possibly lies under a' is the wordplay.
'possibly' indicates an anagram.
'under' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'lies' anagrammed gives 'isle'.
'isle' after 'a' is 'AISLE'.
Can you help me to learn more?
(Other definitions for aisle that I've seen before include "Divide in a church" , "Church walkway" , "Path between seats in church" , "Part of a church" , "Passage between seating areas" .)