Religious observance (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
devotion
'religious observance' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for devotion that I've seen before include "Religious zeal" , "Feelings of ardent love" , "Intense loyalty" , "Dedication" , "Commitment to some purpose, religion say" .)