Highly distasteful (4)
I believe the answer is:
icky
'highly distasteful' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for icky that I've seen before include "Very bad" , "Cloying -- repulsive" , "Nasty, unpleasant (colloq.)" , "Repulsive - distasteful" , "Rotten - unpleasantly gooey" .)