Sour cherry (7)
I believe the answer is:
morello
'sour cherry' is the definition.
(I know that morello is a type of sour cherry)
This is the entire clue.
(Other definitions for morello that I've seen before include "Type of cherry" , "Sour red fruit" , "Variety of sour cherry" , "Dark-red variety of cherry" , "Dark red cherry" .)