What was the slave driver called ancient Rome?

Usually he was called by his name. The Romans had no specific term for "slave driver". Remember, many of our Words/terms in use today are hybrids or a type of slang that because of constant usage has become a legitimate Word. The closest Words that the Romans had for our term "slave driver" were "venalicius" or "mango" which meant slave dealer. There was also the Words "custos" and "curator" which mean overseer.