What is what does dull mean?

Dull refers to something lacking in brightness, shininess, or intensity. It can also refer to something lacking in interest, excitement, or stimulation. When used to describe a person, it might mean that the person is not intelligent or quick-witted. In terms of color, dull colors are not vivid or bright but rather muted and restrained. Additionally, dull can also mean something not sharp or pointed – such as a dull knife or pencil.