Flood finished, predatory beast returned (8)
I believe the answer is:
overflow
'flood' is the definition.
('overflow' can be a synonym of 'flood')
'finished predatory beast returned' is the wordplay.
'finished' becomes 'over' ('over' can be similar in meaning to 'finished').
'predatory beast' becomes 'wolf'.
'returned' says the letters should be written in reverse.
'wolf' back-to-front is 'flow'.
'over'+'flow'='OVERFLOW'
(Other definitions for overflow that I've seen before include "Pipe etc for excess water" , "Spillage of excess liquid" , "Drainage outlet" , "Of water or crowd, spread beyond the usual limits" , "(Outlet for) surplus water" .)