Bombastic display (4)
I believe the answer is:
rant
'bombastic display' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rant that I've seen before include "Talk wildly or violently" , "Intemperate speech" , "Speak intemperately" , "Bombastically declaim" , "Shout wildly at length" .)