Brown Driver Briggs

 Hanun = "gracious"
1. son of Nahash and king of Ammon who dishonoured David's ambassadors
and lost the subsequent war with David
2. a man who, with the people of Zanoah, repaired the ravine gate in
the wall of Jerusalem
3. the 6th son of Zalaph, who also assisted in the repair of the wall
of Jerusalem, apparently on the east side