During the attack on Thebez, a woman dropped an upper millstone on Abimelech’s head and crushed his skull (Judges 9:53). He told his armor-bearer to kill him so it would not be said a woman killed him, and the armor-bearer did so (Judges 9:54).
In Judges 9:50–55, Abimelech moves from one assault to another, besieging Thebez and pressing an attack against a fortified tower where the town has taken refuge. As he approaches the tower’s entrance to set it on fire, an unnamed woman drops a large stone that crushes his skull. This scene concludes the Abimelech episode in Judges 9, where Abimelech has seized power through violence and then faces escalating resistance and internal collapse. The narrative has moved from his rise at Shechem, to betrayal and conflict, to ruthless reprisals against cities that oppose him.
This short scene ends Abimelech’s violent rise with a sudden reversal. The text’s main movement is straightforward: Abimelech captures Thebez but cannot immediately take its inner refuge (the strong tower). When he closes in to burn the door, an unnamed woman drops an “upper millstone” that crushes his skull.
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Judges 9:53, then read the surrounding section so the answer stays connected to the passage's flow.
53A certain woman cast an upper millstone on Abimelech`s head, and broke his skull.