The Speaker’s faction expressed their disappointment? (6)
I believe the answer is:
sighed
'expressed their disappointment?' is the definition.
(a sigh might express disappointment)
'the speaker's faction' is the wordplay.
'the speaker's' shows a homophone (sound like) (as it might sound when spoken).
'faction' becomes 'side' (one side in a conflict or controversy).
'side' sounds like 'SIGHED'.
(Other definitions for sighed that I've seen before include "Moaned" , "Exhaled audibly" , "He digs ( anag.)" , "Breathed wearily" , "Made sad sound" .)