Crossbreed (7)
'crossbreed?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mongrel that I've seen before include "bastard" , "Mixed-breed dog" , "of mixed blood" , "Cross" , "Cur" .)
(Other definitions for maltese that I've seen before include "From Valletta, perhaps" , "Description of cross" , "Pigeon" , "sort of cross" , "Eg, native of Valletta" .)
'crossbreed' is the definition.
(I know that crossbreed can be written as hybrid)
This is all the clue.
(Other definitions for hybrid that I've seen before include "Offspring of mixed parents" , "Crossbreed or mixture" , "Compound, mixture" , "(One) of mixed origin" , "Of mixed character" .)