Opponents in bridge contract appeal (8)
I believe the answer is:
entreaty
'appeal' is the definition.
(synonyms)
'opponents in bridge contract' is the wordplay.
'opponents' becomes 'en' (I've seen this in other clues).
'in bridge contract' becomes 'treaty' (I can't justify this - if you can you should give a lot more credence to this answer).
'en'+'treaty'='ENTREATY'
Can you help me to learn more?
(Other definitions for entreaty that I've seen before include "petition" , "suit" , "Earnest plea" , "Appeal" , "application for assistance" .)