Screens bank for weakness (5,4)
I believe the answer is:
blind spot
'weakness' is the definition.
(I've seen this in another clue)
'screens bank' is the wordplay.
'screens' becomes 'blinds' (blind is a kind of screen).
'bank' becomes 'pot' (I am not sure about this - if you are sure you should believe this answer much more).
'blinds'+'pot'='BLIND SPOT'
'for' is the link.
Can you help me to learn more?
(Other definitions for blind spot that I've seen before include "source of misunderstanding?" , "where one cannot see" , "Area where understanding is lacking or one is unsighted" , "Hazard for driver" , "Unseen area of road" .)