Fairly beautiful (6)
I believe the answer is:
pretty
I believe this clue is a double definition.
'fairly' is the first definition.
(thesaurus)
'beautiful' is the second definition.
('pretty' can be similar in meaning to 'beautiful')
(Other definitions for pretty that I've seen before include "comely" , "See 19" , "charming to look at" , "Pleasing on the eye" , "Somewhat - attractive" .)