but you have risen up against my father’s house this day and have slain his sons, 70 men on one stone, and have made Abimelech, the son of his female servant, king over the leaders of Shechem, because he is your brother— Bible see other translations

“his female servant.” This is even more derogatory than “concubine,” which while a wife of lesser status, is still a wife. Jotham seems to be being purposely derogatory.

Commentary for: Judges 9:18