Disbarment means that a lawyer is not allowed to be a lawyer anymore. Just like little kids can get in trouble and be punished for doing bad things, lawyers can also get in trouble and be punished for breaking rules. If a lawyer does something really bad, like lying or stealing from their clients, they can be disbarred.
Being a lawyer is a big responsibility. They have to follow lots of rules and laws to make sure they are doing their job right. If a lawyer breaks those rules or does something wrong, they might not be allowed to be a lawyer anymore. That's what disbarment means.