What is the meaning of "Morech"?
Rashi: "Morech", from the root 'Rach', implies both 'terrified' and 'weak hearted'.
Targum Onkelos and Targum Yonasan: It means that Hashem will cause them to become broken (or shattered).
What does "Venasu Menusas Cherev" mean?
Rashi and Targum Yonasan: 'They will flee as if the enemy is chasing them (with swords drawn)'.
And what does "ke'Kol Aleh Nidaf" mean?
Rashi (citing Targum Onkelos): It means that even the sound of one leaf banging 1 against another will frighten them.
Targum Yonasan: It means like a leaf falling from a tree.