Definition of dull

The word "dull" has its roots in Old English. The adjective "dull" originally meant "not sharp or keen" and was used to describe something that lacked brightness or sharpness, whether it was a physical object, a mental faculty, or a sense. This sense of "dull" as "lacking in sharpness" is still in use today, as in the phrase "dull knife." Over time, the meaning of "dull" expanded to include connotations of lack of interest, excitement, or stimulation. Something that is dull can be described as unengaging, monotonous, or soporific. This usage is thought to have developed from the idea that something that is dull lacks the sharpness or brightness needed to capture one's attention. Today, the word "dull" is used to describe not just physical objects, but also emotions, experiences, and even people.