Synonyms for Flatness:

n.

sterileness, weariness, asepticism, excite, stodginess, drabness, jejuneness, dryness, lifelessness, colorlessness, flavorlessness, sterility, insipidness, dreariness, vapidness. attribute (noun)
two-dimensionality, planeness.
dullness (noun)
dreariness, stodginess, drabness, staleness, insipidness, vapidity, insipidity, asepticism, sterileness, dryness, colorlessness, flavorlessness, jejuneness, vapidness, blandness, lifelessness.
flatness (noun)
evenness, lusterlessness, mat, planeness, lustrelessness, Flushness, two-dimensionality, horizontality, matte, matt, Levelness.
horizontality (noun)
planarity.
non-resonance (noun)
silence, non-resonance, dullness, muteness, deadness.
prairie (noun)
plateau, pampas, savanna, champaign, countryside, heath, prairie, steppe, moor, plain, tundra, desert, veld, mesa.
prostration (noun)
vapidness, weariness, vapidity.
tastelessness (noun)
tastelessness, plainness, insipidity, mildness, staleness, banality, unsavoriness, blandness, vapidity, weakness.

Other synonyms:

sterileness, lifelessness, colorlessness, flavorlessness, vapidness, dreariness, stodginess, asepticism, drabness. jejuneness, insipidness. weariness, dryness. sterility. Other relevant words:
asepticism, matt, lusterlessness, dreariness, weariness, sterileness, vapidness, mat, lustrelessness, stodginess, colorlessness, matte, flavorlessness, jejuneness, lifelessness, two-dimensionality, dryness, insipidness, drabness, sterility, planeness.

Usage examples for flatness

  1. It's very dreadful, Mrs. Jervaise said; and then Olive slightly lifted the awful flatness of the dialogue by saying,- We ought to have guessed. – The Jervaise Comedy by J. D. Beresford
  2. But Sancho was on his feet in an instant, and began to grapple with his master, and he crushed his emaciated body almost to flatness in his firm grip. – The Story of Don Quixote by Arvid Paulson, Clayton Edwards, and Miguel de Cervantes Saavedra
  3. The Connecticut is here tame and uninteresting, with near shores of salt- marsh flatness – Nooks and Corners of the New England Coast by Samuel Adams Drake