Stomabeutel and wandr: “Put down” is a synonym for “make fun of” or “insult” in the US. I’ve definitely heard Brits say it as well, but I do think it might be a predominately Stateside thing. Unless you’re in the States, in which case … you just don’t know a very, very common term.
We also use “put down” to mean “kill,” but that’s usually reserved for animals. I personally don’t remember ever having heard that phrase used to apply to humans.
i use the phrase “put down” all the time in reference to a human being…I live in America. “To say something about somebody or something in a negative way sometimes in a joke, also known as a cut down.” -as defined by urbandictionary.com.