mutt

noun

1. A mongrel dog (or sometimes cat); an animal of mixed breed or uncertain origin.

   “Mr. Beerbelly, Beerbelly / Get these mutts away from me / You know, I don't find this stuff amusing anymore”

2. (derogatory, humorous, usually)A person of mixed racial or ethnic ancestry.

   “Soon, we will no longer be an outpost of Europe, but a nation of mutts, a nation with hundreds of fluid ethnicities from around the world, intermarrying and intermingling. Americans of European descent are already a minority among 5-year-olds. […] Immigration reform or not, the nation of mutts is coming.”

3. (Internet, broadly, derogatory)A person from the United States.
4. (US, derogatory, slang)An idiot, a stupid person.

   ““I knew you weren’t such a mutt as you looked,” she cried.”

   “I must say I think Chloe was a bit of a mutt to walk on the bed and then leave a button somewhere about. She might have learned better than that from the pictures surely.”

   “Mother fuckin' mutt! You, you fucking piece of shit!”

   ““He’s so blatantly stupid. He’s a punk. He’s a dog. He’s a pig. A con. A bullshit artist. A mutt who doesn’t know what he’s talking about,” he said, among many other things, in a video.”

5. (slang)The snowy sheathbill.
6. (alt-of, alternative)Alternative form of matha.