Scum

I taught my English Club how to play "Scum" today. "What is scum?" they asked. Hmmm, I hadn't thought that definition through, so I replied, "You know that stuff at the bottom of ponds?" They seemed to get the drift, but for all I know, they may now think scum is a synonym for mud...or fish. So, in the future, if you meet a young person from Andong who responds with "scum" when you're pointing at koi...uhhh blame the Japanese.