Inauspicious (3-6)
'inauspicious' is the definition.
(thesaurus)
This is the entire clue.
'inauspicious' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for adverse that I've seen before include "negative result" , "Contrary -- inauspicious" , "Contrary, harmful" , "Detrimental" , "'Contrary, untoward (7)'" .)