Dull  —adj. 1 tedious; not interesting. 2 (of the weather) overcast. 3 (of colour, light, sound, etc.) Not bright, vivid, or clear. 4 (of a pain) indistinct; not acute (a dull ache). 5 slow-witted; stupid. 6 (of a knife-edge etc.) Blunt. 7 a (of trade etc.) Sluggish, slow. B listless; depressed. 8 (of the ears, eyes, etc.) Lacking keenness. —v. Make or become dull.  dullness n. Dully adv. [low german or dutch]