Brown Driver Briggs

 Jair = "he enlightens"
1. a descendant of Manasseh who conquered many towns during the time
of the conquest
2. the Gileadite, a judge of Israel for 22 years during the time of
the judges; father of 30 sons
3. a Benjamite, son of Kish, and father of Mordecai
4. father of Elhanan, one of David's mighty warriors