Gran on it turned out to be unenlightened (8)
I believe the answer is:
ignorant
'be unenlightened' is the definition.
(synonyms)
'gran on it turned out' is the wordplay.
'turned out' is an anagram indicator (turn out can mean to organise).
'gran'+'on'+'it'='granonit'
'granonit' anagrammed gives 'IGNORANT'.
'to' is the link.
(Other definitions for ignorant that I've seen before include "Illiterate - unaware" , "Empty-headed" , "Ill-educated" , "Lacking knowledge or awareness" , "blissful?" .)