Brown Driver Briggs

 Mephibosheth = "exterminating the idol"
1. grandson of Saul and son of Rizpah the daughter of Aiah, Saul's
concubine; he and his brother Armoni were among the 7 victims
surrendered by David to the Gibeonites to avert a famine
2. son of Jonathan and grandson of Saul
  1) also 'Merib-baal'