flatness

noun

1. the property of having two dimensions
2. a want of animation or brilliance"the almost self-conscious flatness of Hemingway's style"
3. a deficiency in flavor"it needed lemon juice to sharpen the flatness of the dried lentils"
4. the property of having little or no contrast; lacking highlights or gloss
5. inactivity; showing an unusual lack of energy"the general appearance of sluggishness alarmed his friends"