dull

(verb): To render dull; to remove or blunt an edge or something that was sharp.
(verb): To soften, moderate or blunt; to make dull, stupid, or sluggish; to stupefy.
(verb): To lose a sharp edge; to become dull.
(verb): To render dim or obscure; to sully; to tarnish.
(adjective): Lacking the ability to cut easily; not sharp.
(adjective): Boring; not exciting or interesting.
(adjective): Not shiny; having a matte finish or no particular luster or brightness.
(adjective): Not bright or intelligent; stupid; having slow understanding.
(adjective): Sluggish, listless.
(adjective): Cloudy, overcast.
(adjective): Insensible; unfeeling.
(adjective): Heavy; lifeless; inert.
(adjective): (of pain etc) Not intense; felt indistinctly or only slightly.
(adjective): (of a noise or sound) Not clear, muffled.