Portents (5)
I believe the answer is:
omens
'portents' is the definition.
('omen' can be a synonym of 'portent')
This is all the clue.
(Other definitions for omens that I've seen before include "Portents, prophetic signs" , "Prognostications" , "Signs or warnings for the future" , "Auguries" , "Prophetic signs of good or evil" .)