Bad sign, perhaps (4)
I believe the answer is:
omen
'bad sign perhaps' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for omen that I've seen before include "Portent, prophetic indicator" , "Foreshadow" , "writing on the wall" , "Foreboding" , "Sign of likely future event" .)