Outpouring from rotter in lawsuit (7)
I believe the answer is:
cascade
'outpouring' is the definition.
(I've seen this in another clue)
'rotter in lawsuit' is the wordplay.
'rotter' becomes 'cad' (I've seen this before).
'in' indicates putting letters inside.
'lawsuit' becomes 'case' (a legal case).
'cad' put into 'case' is 'CASCADE'.
'from' acts as a link.
(Other definitions for cascade that I've seen before include "Waterfall or deluge" , "falls in the river" , "Sudden downpour" , "Series of small waterfalls" , "Dramatic fall" .)