Favour one pressing a suit (8)
I believe the answer is:
advocate
This clue could be a double definition.
'favour' is the first definition.
The answer and definition can be both to do with communicating as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
'one pressing a suit' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
Can you help me to learn more?
(Other definitions for advocate that I've seen before include "Publicly support (cause)" , "Speak in favour of" , "Defender" , "Caveat, do about lawyer in court" , "Recommend - person acting on another's behalf" .)