a question of vocabulary

Some of you may remember that I asked a few weeks ago if anyone knew what the word "choam" meant. My brother had called his friend a "choam" but he was too embarrassed to tell me what it meant. So I asked everyone I knew, even my students. No one could explain it to me.

Well, we were talking on the phone today, and I told my brother that he and his friends must have made the stupid word up, because no one I know has ever heard of it. "Stephanie," he replied in tones of great disgust that only a 16-year-old boy can have for his hopelessly nerdy older sister. "I called him a choad, not a choam. Just google it and leave me alone."

I still have no idea what a choad is. And I have to admit that it's driving me crazy. Can anybody help? Please?