\Flat"ness\, n.
1. The quality or state of being flat.
2. Eveness of surface; want of relief or prominence; the
   state of being plane or level.
3. Want of vivacity or spirit; prostration; dejection;
   depression.
4. Want of variety or flavor; dullness; insipidity.
5. Depression of tone; the state of being below the true
   pitch; -- opposed to {sharpness} or {acuteness}.