dullness without sharpness or clearness of edge or point; "the dullness of the pencil made his writing illegible"
flatness -
a want of animation or brilliance; "the almost self-conscious flatness of Hemingway's style"
expressive style,
style a way of expressing something (in language or art or music etc.) that is characteristic of a particular person or group of people or period; "all the reporters were expected to adopt the style of the newspaper"
flatness -
a deficiency in flavor; "it needed lemon juice to sharpen the flatness of the dried lentils"