I. adjective
1.
Synonyms: stupid 1, beef-witted, blear-witted, dense, doltish, dumb, duncical, numskulled, thick, thick-witted
Antonyms: sharp
2.
Synonyms: retarded , backward, dim-witted, feebleminded, half-witted, imbecile, moronic, simple, simpleminded, slow
Contrasted words: advanced, precocious
3.
Synonyms: insensible 5, anesthetic, bloodless, hard, impassible, insensate, insensitive, rocky
4.
Synonyms: downcast , bad, blue, cast down, dejected, depressed, dispirited, down, downhearted, spiritless
5.
Synonyms: colorless 2, drab, flat, lackluster, lifeless, lusterless, prosaic, prosy
Antonyms: bright
6.
lacking sharpness of edge or point
a knife with a dull blade
Synonyms: blunt, obtuse
Related Word: blunted, dulled, unsharpened
Contrasted words: honed, keen, razor-sharp, unblunted, whetted
Antonyms: sharp
7.
lacking warmth, luster, or brilliance
a smooth dull finish
Synonyms: blind, dead, dim, flat, lackluster, lusterless, mat, muted
Related Word: cold, dingy, drab, dun, leaden, somber; deadened, lifeless
Contrasted words: beaming, bright, brilliant, effulgent, fulgent, incandescent, lambent, lucent, lucid, luminous, lustrous, radiant, refulgent; burnished, polished, shiny
8.
cloudy in color
a dull brown
Synonyms: drab, muddy, murky, subfusc
Related Word: blurry, cloudy, hazy; flat, lackluster, lifeless, lusterless; mousy
Antonyms: clear; rich
9.
being so unvaried or uninteresting as to provoke boredom or tedium
any routine constantly repeated can become dull
Synonyms: banausic, blah, ||dim, dreary, humdrum, monotone, monotonous, pedestrian, plodding, poky, stodgy
Related Word: boring, irksome, tedious, tiring, wearisome; brainless; exhausting, fagging, fatiguing
Contrasted words: animating, exciting, stimulating; gay, spritely
Antonyms: lively
10.
Synonyms: overcast , cloudy, ||dowly, heavy, lowering ( or louring), nubilous, overclouded
11.
Synonyms: arid 2, bromidic, dry, dryasdust, dusty, insipid, tedious, uninteresting, weariful, wearisome
Related Word: matter-of-fact, prosaic, prosy; bloodless
Idioms: dull as ditchwater
Contrasted words: exciting, stimulating
Antonyms: lively
II. verb
1.
to make less clear, distinct, or bright
colors dulled by the sun
Synonyms: dim, fade, muddy, pale, tarnish
Related Word: discolor, wash out; blur
Contrasted words: brighten, freshen, intensify
2.
Synonyms: deaden 1, benumb, blunt, desensitize, mull, numb
Antonyms: sharpen
3.
to deprive of sharpness (as of edge or point)
dull a spade
Synonyms: blunt, disedge, obtund, turn
Idioms: take the edge off
Contrasted words: edge, hone
Antonyms: sharpen
4.
to impair one or more of the senses
age had dulled his hearing
Synonyms: blear, blur, dim
Related Word: debilitate, enfeeble, weaken; darken; retard, slow
Antonyms: sharpen
5.
to make slow or obtuse
his mind had been dulled by drink
Synonyms: blunt, hebetate, stupefy
Related Word: becloud, befog, cloud, darken, dim; benumb, deaden, numb; retard, slow
Contrasted words: quicken, stimulate, whet
Antonyms: sharpen