Hybrid; mutt (7)
I believe the answer is:
I believe this clue is a double definition.
'hybrid' is the first definition.
(I've seen this before)
'mutt' is the second definition.
(I know that mutt can be written as mongrel)
(Other definitions for mongrel that I've seen before include "Dog of mixed breed" , "Cross" , "of mixed blood" , "bastard" , "Dog of no recognisable breed" .)