Noah Webster's Dictionary (n.) The quality or state of being simple; simplicity.

Multi-Version Concordance Simpleness (2 Occurrences) Proverbs 1:22 How long, simple ones, will ye love simpleness, and scorners take pleasure in their scorning, and the foolish hate knowledge? (DBY) Proverbs 9:6 Forsake ye, the simple, and live, And be happy in the way of understanding. (See RSV)