More unpleasant to look at (6)
I believe the answer is:
uglier
'more unpleasant to look at' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for uglier that I've seen before include "Less pleasing to the sight" , "More unsightly" , "Less pleasing to look at" , "More lacking in beauty" , "more revolting" .)