Speak pompously, hold forth (5)
I believe the answer is:
orate
This clue is a double definition.
'speak pompously' is the first definition.
(to orate is to give a speech)
'hold forth' is the second definition.
(I've seen this before)
(Other definitions for orate that I've seen before include "Give a formal address" , "Speak publicly" , "Pontificate" , "Give speech" , "Make a formal speech" .)