Went under (4)
'went under' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dove that I've seen before include "Bird in the pigeon family" , "Bird representing peace" , "Pigeon-like bird" , "Symbol of peace" , "Peacemaker" .)
'went under' is the definition.
('sink' can be a synonym of 'go under')
This is the entire clue.
(Other definitions for sank that I've seen before include "Subsided" , "Scuttled" , "Foundered" , "Fell to the bottom" , "(Of ship) went down" .)
(Other definitions for failed that I've seen before include "Was unsuccessful, did not pass exam" , "Didn't succeed" , "Bankrupt" , "Did not succeed, perhaps at exam" , "Didn't make it - not well" .)