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