In the Bible, "vanity" means that something is meaningless. It has no value, and therefore, it is a waste of time to chase after this item. Vanity is a word found throughout the Bible, which indicates its importance to the lessons being taught.
In Ecclesiastes 5:10, it is written that "He who loves money will not be satisfied with money, nor he who loves abundance with its income. This too is vanity." This means that the quest for money and abundance will not bring true happiness, as the quest simply continues endlessly. If a person loves money, he will continue to strive for more instead of being satisfied with what he has.
Another passage in the same book, Ecclesiastes 4:16, says "for this too is vanity and striving after wind." No one can catch the wind, and it is pointless to try.