Be a sign of (4)
I believe the answer is:
bode
'be a sign of' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bode that I've seen before include "Augur, foreshadow" , "Presage" , "Augur (well, badly)" , "Portend, foretell" , "Waited" .)