The meaning of “יְשֻׁרוּן”

“But Jeshurun waxed fat, and kicked: thou art waxen fat, thou art grown thick, thou art covered with fatness; then he forsook God which made him, and lightly esteemed the Rock of his salvation.”

“And he was king in Jeshurun, when the heads of the people and the tribes of Israel were gathered together.”

“There is none like unto the God of Jeshurun, who rideth upon the heaven in thy help, and in his excellency on the sky.”

“Thus saith the Lord that made thee, and formed thee from the womb, which will help thee; Fear not, O Jacob, my servant; and thou, Jesurun, whom I have chosen.”