Not a pretty sight (7)
I believe the answer is:
eyesore
'not a pretty sight' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eyesore that I've seen before include "pigsty" , "ugly feature" , "Unpleasant sight" , "Something exceedingly ugly" , "Blot on the landscape" .)