Glories in ruined churches (9)
I believe the answer is:
religions
'churches' is the definition.
('religion' can be a synonym of 'church')
'glories in ruined' is the wordplay.
'ruined' indicates anagramming the letters.
'glories'+'in'='gloriesin'
'gloriesin' with letters rearranged gives 'RELIGIONS'.
(Other definitions for religions that I've seen before include "Organised beliefs" , "Organised systems of faith and worship" , "Systems of belief" .)