The Hebrew interjection oy (אוֹי) is an exclamation of grief, distress, or lamentation — equivalent to the English woe or alas. It functions both in personal lament and in the formal prophetic woe oracles pronouncing divine judgment.
The prophetic woe oracles represent God's solemn declaration of coming judgment upon the wicked and rebellious. Isaiah's six woes (chapter 5) condemn social injustice, greed, and pride. These are not merely grief but divine pronouncements carrying covenantal authority. They invite repentance while warning of consequence — echoing through to Jesus' own woe declarations in Matthew 23.