flatness

(noun) the property of having two dimensions. Synonyms: two-dimensionality, planeness.

(noun) a want of animation or brilliance. Examples: "The almost self-conscious flatness of hemingway's style."

(noun) a deficiency in flavor. Examples: "It needed lemon juice to sharpen the flatness of the dried lentils."

(noun) the property of having little or no contrast; lacking highlights or gloss. Synonyms: lusterlessness, lustrelessness, mat, matt, matte.

(noun) inactivity; showing an unusual lack of energy. Synonyms: languor, lethargy, sluggishness, phlegm. Examples: "The general appearance of sluggishness alarmed his friends."