Not prepared (7)
I believe the answer is:
unready
'not prepared' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for unready that I've seen before include "Like one English king" , "Ill prepared" , "Disobedient in a scout" , "Ethelred, the ..., old English king" , "Not prepared (like Ethelred?)" .)