Very grievous— The Vulgate renders it innumerable; and so the original word sometimes signifies. But it seems here rendered, more properly, and more agreeable to the context, grievous.
Related Commentaries of Exodus 10:14
Exodus 10:14
14 And the locusts went up over all the land of Egypt, and rested in all the coasts of Egypt: very grievous were they; before them there were no such locusts as they, neither after them shall be such.