Belted hunter scoffing at speech (7)
I believe the answer is:
oration
'speech' is the definition.
(oration is a kind of speech)
'belted hunter scoffing at' is the wordplay.
'belted hunter' becomes 'orion' (the constellation Orion the hunter has a belt).
'scoffing' is an insertion indicator.
'orion' going around 'at' is 'ORATION'.
(Other definitions for oration that I've seen before include "Ontario (anag)" , "Major speech" , "lecture" , "eulogy" , "Making a speech" .)