1.Definition: a deficiency in flavor

"It needed lemon juice to sharpen the flatness of the dried lentils"

Category: General

2.Definition: a want of animation or brilliance

"The almost self-conscious flatness of Hemingway's style"

Category: General

3.Definition: inactivity; showing an unusual lack of energy

Related Noun(s):languor, lethargy, phlegm, sluggishness

Category: General

4.Definition: the property of having little or no contrast; lacking highlights or gloss

Related Noun(s):lusterlessness, lustrelessness, mat, matt, matte

Category: General

5.Definition: the property of having two dimensions

Related Noun(s):planeness

Category: General