Cathedral part (4)
I believe the answer is:
nave
'cathedral part' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nave that I've seen before include "Take no risks" , "Part of the church sounds like a rogue" , "Main part of a church" , "Central part of church" , "The hub of a wheel, or body of church" .)