Sighed word (4)

I believe the answer is:
alas
'sighed word' 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 "-- and alack!" , "Woeful expression" , "Proper, respectable" , "Interjection of sorrow" , "Antipodean island state" .)