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