Meaning

• The quality of being slow of understanding things; stupidity.

• The quality of being uninteresting; boring or irksome.

• Lack of interest or excitement.

• The lack of visual brilliance; want of sheen.

  "dullness of autumn"

• (of an edge) bluntness.

• The quality of not perceiving or kenning things distinctly.

  "dullness of sight, or of hearing"

• Drowsiness.