Partner of circumstance (4)
I believe the answer is:
pomp
'partner of circumstance' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pomp that I've seen before include "Ceremony or ostentation" , "Solemn ceremony and splendid display" , "Great show" , "Vain display" , "Ceremonial grandeur" .)