"Vanity" was one of the first biblical words I learned as a new Christian. Ecclesiastes really spoke to me then as a college student. Summum bonum is the "highest good", i.e., God's glory and blessedness. Vanity is what's left when we forfeit ultimate Value.
If not in honor, beauty, age, nor treasure,
Nor yet in learning, wisdom, youth, nor pleasure,
Where shall I climb, sound, seek, search, or find
That summum bonum which may stay my mind?
There is a path no vulture's eye hath seen,
Where lion fierce, nor lion's whelps have been,
Which leads unto that living crystal fount,
Who drinks thereof, the world doth naught account.
This pearl of price, this tree of life, this spring,
Who is possessed of shall reign a king.
Nor change of state nor cares shall ever see,
But wear his crown unto eternity.
This satiates the soul, this stays the mind,
And all the rest, but vanity we find.
--from The Vanity of All Worldly Things, by Anne Bradstreet, Puritan wife and America's first female poet.