Fall of villain in lawsuit (7)
I believe the answer is:
cascade
'fall' is the definition.
(cascading is a kind of falling)
'villain in lawsuit' is the wordplay.
'villain' becomes 'cad' (cad is a kind of villain).
'in' indicates putting letters inside.
'lawsuit' becomes 'case' ('case' can be a synonym of 'lawsuit').
'cad' inserted inside 'case' is 'CASCADE'.
'of' acts as a link.
(Other definitions for cascade that I've seen before include "Outpouring" , "Sudden downpour" , "Torrent" , "Shower" , "falls in the river" .)