Established religious ceremony (4)
I believe the answer is:
rite
'established religious ceremony' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rite that I've seen before include "Tries awkwardly to perform rituals" , "Customary observance" , "Established religious ceremony" , "Ceremonial procedure" , "Solemn ceremony" .)