The one right here (4)
I believe the answer is:
this
'the one right here' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for this that I've seen before include "The thing here referred to" , "Hits (anag.)" , "The thing under discussion" , "What's here" , "Pronoun to point out nearby things" .)