Brown Driver Briggs

 Shammah = "astonishment"
1. son of Reuel, grandson of Esau, and a chief of Edom
2. the 3rd son of Jesse and a brother of David
3. son of Agee the Hararite and one of the 30 of David's mighty warriors
4. the Harodite, one of the 30 of David's mighty warriors
5. another Hararite, one of the 30 of David's mighty warriors