What is the meaning of Dull?

Lacking the ability to cut easily; not sharp.

Boring; not exciting or interesting.

Not shiny; having a matte finish or no particular luster or brightness.

Not bright or intelligent; stupid; having slow understanding.

Sluggish, listless.

Bored, depressed, down.

Cloudy, overcast.

Insensible; unfeeling.

Heavy; lifeless; inert.

Not intense; felt indistinctly or only slightly.

Not clear, muffled.

To render dull; to remove or blunt an edge or something that was sharp.

To soften, moderate or blunt; to make dull, stupid, or sluggish; to stupefy.

To lose a sharp edge; to become dull.

To render dim or obscure; to sully; to tarnish.

scupper

bung-hole

method

Source: wiktionary.org