Small clip around ear finally, or back of neck (6)
I believe the answer is:
scruff
'back of neck' is the definition.
(informal term for the back of someone's neck)
'small clip around ear finally' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'clip' becomes 'cuff' (both can mean to hit or beat).
'around' means one lot of letters goes inside another.
'finally' says to take the final letters.
The final letter of 'ear' is 'r'.
'cuff' placed around 'r' is 'cruff'.
's'+'cruff'='SCRUFF'
'or' is the link.
(Other definitions for scruff that I've seen before include "One probably wouldn't wash" , "Untidy chap" , "Unkempt individual" , "Back of a cat's neck" , "bit of neck?" .)