Uninformed (8)
'uninformed' is the definition.
(I know that uninformed can be written as ignorant)
This is all the clue.
(Other definitions for ignorant that I've seen before include "Unaware, uninformed" , "Lacking knowledge or awareness" , "Discourteous" , "Ill-educated" , "No rating (anag) - in the dark" .)
(Other definitions for clueless that I've seen before include "Ignorant; helpless" , "not like our solvers!" , "sort of crossword that nobody can solve?" , "Lacking knowledge and ability (informal)" , "such a crossword can't be solved!" .)