Religious sanctimonious practice following Sabbath (9)
I believe the answer is:
spiritual
'religious' is the definition.
('spiritual' can be a synonym of 'religious')
'sanctimonious practice following sabbath' is the wordplay.
'sanctimonious' becomes 'pi'.
'practice' becomes 'ritual' (ritual is a kind of practice**).
'following' means one lot of letters go next to another.
'sabbath' becomes 's'.
'pi'+'ritual'='piritual'
'piritual' put after 's' is 'SPIRITUAL'.
(Other definitions for spiritual that I've seen before include "Relating to religion" , "Relating to the holy or divine" , "Relating to religious belief" , "Sacred - Black American religious song" , "concerning religion" .)