A mongrel dog (or sometimes cat); an animal of mixed breed or uncertain origin.
"The old dictionary entry for mutt listed it as an alternative spelling for matha, a word referring to the forehead in Hindi and Urdu dialects."
Alternative form of matha
Mutt is a shortened form of the word muttonhead, which originally referred to a foolish or stupid person. The term eventually came to describe any mixed-breed dog, likely due to their varied and sometimes unpredictable appearance.