Bemoan, mourn (6)
I believe the answer is:
lament
I believe this clue is a double definition.
'bemoan' is the first definition.
(I know that bemoan can be written as lament)
'mourn' is the second definition.
(I've seen this in another clue)
(Other definitions for lament that I've seen before include "Mourning song or poem" , "Dart-throwing line" , "Mourn (a person's death)" , "Cry of sorrow" , "Express disappointment" .)