Bridge partners finding two highest cards unconvincing (4)
I believe the answer is:
weak
'unconvincing' is the definition.
(I've seen this in another clue)
'bridge partners finding two highest cards' is the wordplay.
'bridge partners' becomes 'we' (West and East are players in the card game bridge).
'finding' says to put letters next to each other.
'two highest cards' becomes 'ak' (I can't explain this - if you can you should give a lot more credence to this answer).
'we'+'ak'='WEAK'
Can you help me to learn more?
(Other definitions for weak that I've seen before include "Puny" , "Spent" , "Easily led" , "lacking intensity?" , "Lacking strength" .)