Daughters break bank (5)
I believe the answer is:
drift
'bank' is the definition.
(I've seen this before)
'daughters break' is the wordplay.
'daughters' becomes 'd' (genealogical abbreviation for daughters).
'break' becomes 'rift' (rift can mean a break or opening).
'd'+'rift'='DRIFT'
(Other definitions for drift that I've seen before include "aimless" , "non-standard deviation?" , "General meaning or flow" , "General trend - current travel" , "Wander aimlessly" .)