Floyd Mayweather -- Rips Chrissy Teigen ... Back Off My Tiger!

Floyd Mayweather is ANGRY that Chrissy Teigen would dare insult his decision to get a pet tiger -- and now he's lashing out at the supermodel over it.

After Mayweather revealed his new pet -- Teigen went to Twitter and wrote, "I'm okay with people having pet tigers because it increases their chances of being eaten by a tiger."

Well, Floyd no likey -- 'cause he just appeared on FightHype.com and fired off some not-so-subtle insults right back at her.

"John Legend's wife said something? I've never had anything negative to say about John Legend. I really don't even know what his wife does."

Ouch.

And then the worst insult a supermodel can get -- "I never seen John Legend's wife in my life. And if I did I probably just don't remember it."

Ouch again.