Back of the skull (7)
I believe the answer is:
occiput
'back of the skull' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for occiput that I've seen before include "bit of the bonce" , "Back part of the skull" , "Back of the head (anatomy)" , "Head's back" , "back of one's head" .)