Start off banquet as one at table (4)
I believe the answer is:
'one at table' is the definition.
(one of the four players at a bridge table)
'start off banquet' is the wordplay.
'start off' means to remove the first letter (I've seen 'starting off' mean this (the starting letter is removed)).
'banquet' becomes 'feast' (synonyms).
'feast' with its first letter removed is 'EAST'.
'as' acts as a link.
(Other definitions for east that I've seen before include "4 dn 17 dn", "E", "Ninety degree bearing", "Bearing of 90 degrees", "To right if facing North".)