Not aware a French ruler now is entering (9)
I believe the answer is:
'not aware' is the definition.
(I've seen this before)
'a french ruler now is entering' is the wordplay.
'a french' becomes 'un' ('a' in French).
'ruler' becomes 'king' (king is a kind of ruler).
'is entering' indicates putting letters inside.
'king' enclosing 'now' is 'knowing'.
(Other definitions for unknowing that I've seen before include "Not aware" , "Ignorance" , "Lacking awareness" , "Ignorant" .)