Definition of "jehu"

Among those who seemed disposed to join in this opinion was the Jehu of the Warwickshire coach, who expressed his conviction to our hero, that "he wos a young gent as had much himproved hisself since he tooled him up to the Warsity with his guvnor."

1850s, Cuthbert M. Bede, The Adventures of Mr. Verdant Green