'Grievous' in the Bible

Yahweh did so; and there came grievous swarms of flies into the house of Pharaoh, and into his servants' houses: and in all the land of Egypt the land was corrupted by reason of the swarms of flies.

behold, the hand of Yahweh is on your livestock which are in the field, on the horses, on the donkeys, on the camels, on the herds, and on the flocks with a very grievous pestilence.

Behold, tomorrow about this time I will cause it to rain a very grievous hail, such as has not been in Egypt since the day it was founded even until now.

The locusts went up over all the land of Egypt, and rested in all the borders of Egypt. They were very grievous. Before them there were no such locusts as they, neither after them shall be such.