Obnoxious (6)
I believe the answer is:
odious
'obnoxious' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for odious that I've seen before include "Detestable, execrable" , "Loathsome and repulsive" , "Replusive, abhorrent (6)" , "Comparisons are said to be thus" , "Unequivocally detestable" .)