Part of the neck (6)
I believe the answer is:
scruff
'part of the neck' is the definition.
('scruff' is part of 'neck')
This is all the clue.
(Other definitions for scruff that I've seen before include "Part of neck" , "bit of neck?" , "The back side of the neck" , "Back of the neck, used to lift cat" , "Untidy person - nape of neck" .)