Woeful exclamation (4)
I believe the answer is:
alas
'woeful exclamation' 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 "Expression of grief/pity" , "Sad to say!" , "woebegone expression" , "More's the pity" , "'- Poor Yorick' (Hamlet)" .)