Open Question: What does the slang “dirt” mean?

I was outside my apartments today and was playing basketball with different people. Not that race is an issue but as far as urban slang goes, I was the minority. I was doing good and scoring a lot against this one guy, and they said I was "dirt" and I sort of got the nickname "Dirt". I have never heard anyone use that term before, or while playing basketball, so is that good or bad?