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; inspidity.
5.
Depression of tone; the state of being below the true pitch; -- opposed to sharpness or acuteness.
© Webster 1913.