Kind of as a random thing, I thought of using "Gardez!" because apparently people used to say that when they put the opponents' rooks or queen under direct threat... But when I looked into it on the infinite interwebs, I just keep getting articles about a city "Gardez" in Afghanistan... So I think most people wouldn't get it.
I think many people know that. Also, btw, if you google "chess gardez" you will get relevant hits like https://en.wikipedia.org/wiki/Queen_(chess)
Use what you can Jaws-2. I liked the contradiction.