Sad cry (4)
I believe the answer is:
alas
'sad cry' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for alas that I've seen before include "Proper, respectable" , "Cry of woe" , "'- Poor Yorick' (Hamlet)" , "Too bad, so sad" , "Lackaday" .)