Pontificate but it’s set on mute (5,3)
I believe the answer is:
sound off
'pontificate' is the definition.
The answer and definition can be both to do with communicating as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
'it's set on mute' is the wordplay.
I cannot really understand how this works, but
'set' could be 'do' (synonyms) and 'do' is present in the answer.
This may be the basis of clue (or it may be nonsense).
'but' acts as a link.
Can you help me to learn more?
(Other definitions for sound off that I've seen before include "Complain" , "heard but not seen by audience" , "Rant" , "Voice loud opinions (sl.)" , "keeping the volume right down?" .)