What do you mean by “mbwa”?

Still in the same court, the magistrate refused to issue orders that a petty criminal (PCR) matter be withdrawn until she was made to understand what the accused meant when she called her mother, the complainant, “mbwa”. The accused had been charged with being drunk and disorderly with her charge sheet showing that she insulted her mother in the aforementioned manner. The complainant sought to withdraw. The magistrate’s anger spiked. After giving the accused a thorough dressing down, she instructed a probation officer to investigate the accused, placing keen emphasis on what she meant when she said “mbwa”. To emphasis her point, she called the probation officer to the bench where she showed him the offending word and underlined it. That matter was to be mentioned in two weeks during which the application for withdrawal would be considered against the probation officer’s report.