I believe the answer is:
'hairdresser' is the definition.
(barber is a kind of hairdresser)
This is the entire clue.
(Other definitions for barber that I've seen before include "Traditional men's hairdresser" , "Sweeney Todd's occupation in Fleet Street" , "Men's hairdresser, musically of Seville" , "Men's haircutter, musically of Seville?" , "producing various versions of Hair?" .)