Spoil church procession (5)
I believe the answer is:
march
'procession' is the definition.
(I know that march is a type of procession)
'spoil church' is the wordplay.
'spoil' becomes 'mar' (synonyms).
'church' becomes 'ch' (abbreviation on maps etc).
'mar'+'ch'='MARCH'
(Other definitions for march that I've seen before include "demo" , "that happens fairly early each year" , "Military walking style" , "Month - proceed" , "Stride; month" .)