Dope cut with large narrow hollow (4)
I believe the answer is:
glen
'narrow hollow' is the definition.
'dope cut with large' is the wordplay.
'dope' becomes 'gen' (I've seen this in other clues**).
'cut with' is an insertion indicator.
'large' becomes 'l'.
'gen' enclosing 'l' is 'GLEN'.
(Other definitions for glen that I've seen before include "Scottish or Irish valley" , "Long narrow valley in Scotland" , "Highland valley" , "Depression in Scotland" , "Scottish mountain valley" .)