Portending evil (7)
I believe the answer is:
ominous
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">portending evil</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ominous that I've seen before include "Portending bad things" , "Menacing, sinister" , "'Sinister, baleful (7)'" , "Minatory, trouble coming" , "Portentous" .)