Plainness

King James Dictionary

Pla'Inness, n. Levelness evenness or surface.

1. Want of ornament want of artificial show.

So modest plainness sets off sprightly wit.

2. Openness rough, blunt or unrefined frankness.

Your plainness and your shortness please me well.

3. Artlessness simplicity candor as unthinking plainness. 4. Clearness openness sincerity.

Seeing then we have such hope, we use great plainness of speech.  2 Corinthians 3

Webster's Dictionary

(n.) The quality or state of being plain.