'Vanity' in the Bible

All the nations are like nothing before him. They are regarded by him as less than nothing, and vanity.

Behold, all of them, their works are vanity and nothing. Their molten images are wind and confusion.

But I said, "I have labored in vain, I have spent my strength for nothing and vanity; yet surely the justice [due] to me is with Yahweh, and my reward with my God."

None sues in righteousness, and none pleads in truth: they trust in vanity, and speak lies; they conceive mischief, and bring forth iniquity.