Ceremonial splendour (4)
I believe the answer is:
pomp
'ceremonial splendour' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for pomp that I've seen before include "Ostentatious ceremony" , "Ceremony and splendour" , "Ceremony or ostentation" , "Ceremonial elegance and splendour" , "Vain display" .)