Boi

you say boi when somebody does a very dumb thing or says it.you can also say it when you are about to roast somebody. when you say boi you got to point you hand at the person.

Bob: i hate the U.S i am moving to California.
You: Boi
another example for a roast
Mark: i got this sweet hair cut (terrible hair line)
You: Boi your Hair line looks like 20 mt everests lined up together.