Map out church mural? (5)
I believe the answer is:
chart
'map out' is the definition.
('chart' can be a synonym of 'map out')
'church mural?' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'mural?' becomes 'art' (mural is a kind of art).
'ch'+'art'='CHART'
(Other definitions for chart that I've seen before include "Marine map" , "Map to assist navigation by sea" , "series of plots?" , "Hit parade" , "what could be a pie" .)