Lead-in to bad news (4)
I believe the answer is:
alas
'lead-in to bad news' 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 "Cry of woe" , "Antipodean island state" , "Oh dear!" , "Cry of grief" , "Expression of regret" .)