Repulsive pants? (9)
I believe the answer is:
halitosis
'repulsive pants?' is the definition.
(as in panting - bad breath)
This is the entire clue.
(Other definitions for halitosis that I've seen before include "repulsive pants?" , "Foul breath problem" , "Smelly breath" , "offensive condition" , "Bad breath, smells unpleasant" .)