Fairly easy on the eyes (6)
I believe the answer is:
pretty
I believe this clue is a double definition.
'fairly' is the first definition.
(I know that fairly can be written as pretty)
'easy on the eyes' is the second definition.
(I've seen this in another clue)
(Other definitions for pretty that I've seen before include "Pleasing to look at" , "chocolate-box" , "comely" , "charming to look at" , "Delicately attractive" .)