Unpropitious (7)
I believe the answer is:
adverse
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unpropitious</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for adverse that I've seen before include "Contrary, harmful" , "'Contrary, untoward (7)'" , "Unfavourable or harmful, perhaps criticism" , "'Unfavourable, contrary (7)'" , "Detrimental" .)