- dull [dul]adj.[ME dul < OE dol, stupid, akin to Ger toll < IE * dh(e)wel- < base * dheu-, blow, be turbid > DUMB, DWELL, OIr dall, blind, Gr thanatos, death]1. mentally slow; stupid2. lacking sensitivity; blunted in feeling or perception [dull to grief]3. physically slow; slow-moving; sluggish4. lacking spirit, zest, etc.; not lively; listless, insipid, etc.5. not active or busy; slack [a dull period for sales]6. causing boredom; tedious [a dull party]7. not pointed or sharp; blunt; not keen [a dull blade]8. not felt keenly; not acute [a dull headache]9.a) not vivid; not brilliant; dim [a dull color]b) not shiny or glossy; lusterless [a dull finish]10. not distinct, resonant, etc.; muffled [a dull thud]11. gloomy; cloudy [dull weather]vt., vi.to make or become dullSYN.- STUPIDdullishadj.dullnessn.dulnessdullyadv.SYN.- DULL is specifically applied to a point or edge that has lost its previous sharpness [a dull knife ] and generally connotes a lack of keenness, zest, spirit, intensity, etc. [a dull book, pain, etc. ]; BLUNT is often equivalent to DULL, but specifically refers to a point or edge that is intentionally not sharp [a blunt fencing saber ]; OBTUSE literally applies to a pointed end whose sides form an angle greater than 90°, and figuratively connotes great dullness of understanding or lack of sensitivity [too obtuse to comprehend ] -ANT. SHARP, KEEN1
English World dictionary. V. Neufeldt. 2014.