Banish clubs supporting a porter’s cousin (4,3)
I believe the answer is:
cast out
'banish' is the definition.
(synonyms)
'clubs supporting a porter's cousin' is the wordplay.
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'supporting' says to put letters next to each other (in a down clue, some letters go under others).
'porter's cousin' becomes 'stout' (I can't justify this - if you can you should believe this answer much more).
'c'+'a'+'stout'='CAST OUT'
Can you help me to learn more?
(Other definitions for cast out that I've seen before include "Expelled" , "Expel" , "Rejected from a group" .)