1. (adj)dull lacking in liveliness or animation "he was so dull at parties"; "a dull political campaign"; "a large dull impassive man"; "dull days with nothing to do"; "how dull and dreary the world is"; "fell back into one of her dull moods"
2. (adj)dull emitting or reflecting very littlelight "a dull glow"; "dull silver badly in need of a polish"; "a dull sky"
3. (adj)dull, muffled, muted, softened being or made softer or less loud or clear "the dull boom of distant breaking waves"; "muffled drums"; "the muffled noises of the street"; "muted trumpets"
4. (adj)boring, deadening, dull, ho-hum, irksome, slow, tedious, tiresome, wearisome so lacking in interest as to cause mental weariness "a boring evening with uninteresting people"; "the deadening effect of some routine tasks"; "a dull play"; "his competent but dull performance"; "a ho-hum speaker who couldn't capture their attention"; "what an irksome task the writing of long letters is"- Edmund Burke; "tedious days on the train"; "the tiresome chirping of a cricket"- Mark Twain; "other people's dreams are dreadfully wearisome"
5. (adj)dull (of color) very low in saturation; highly diluted "dull greens and blues"
6. (adj)dull not keenly felt "a dull throbbing"; "dull pain"
7. (adj)dense, dim, dull, dumb, obtuse, slow slow to learn or understand; lacking intellectualacuity "so dense he never understands anything I say to him"; "never met anyone quite so dim"; "although dull at classical learning, at mathematics he was uncommonly quick"- Thackeray; "dumb officials make some really dumb decisions"; "he was either normally stupid or being deliberately obtuse"; "worked with the slow students"
8. (adj)dull, slow, sluggish (of business) not active or brisk "business is dull (or slow)"; "a sluggish market"
9. (adj)dull not having a sharpedge or point "the knife was too dull to be of any use"
10. (adj)dull blunted in responsiveness or sensibility "a dull gaze"; "so exhausted she was dull to what went on about her"- Willa Cather
11. (adj)dull, thudding not clear and resonant; sounding as if striking with or against something relatively soft "the dull thud"; "thudding bullets"
12. (verb)dull, leaden darkened with overcast "a dark day"; "a dull sky"; "the sky was leaden and thick"
13. (verb)dull make dull in appearance "Age had dulled the surface"
14. (verb)dull become dull or lusterless in appearance; lose shine or brightness "the varnished table top dulled with time"
15. (verb)muffle, mute, dull, damp, dampen, tone down deaden (a sound or noise), especially by wrapping
16. (verb)numb, benumb, blunt, dull make numb or insensitive "The shock numbed her senses"
17. (verb)dull, blunt make dull or blunt "Too much cutting dulls the knife's edge"
18. (verb)pall, dull become less interesting or attractive
19. (verb)dull make less lively or vigorous "Middle age dulled her appetite for travel"
Definitions of 'dull'
Webster 1913 Dictionary
1. dull slow of understanding; wanting readiness of apprehension; stupid; doltish; blockish
2. dull slow in action; sluggish; unready; awkward
3. dull insensible; unfeeling
4. dull not keen in edge or point; lacking sharpness; blunt
5. dull not bright or clear to the eye; wanting in liveliness of color or luster; not vivid; obscure; dim; as, a dull fire or lamp; a dull red or yellow; a dull mirror
7. dull furnishinglittle delight, spirit, or variety; uninteresting; tedious; cheerless; gloomy; melancholy; depressing; as, a dull story or sermon; a dull occupation or period; hence, cloudy; overcast; as, a dull day
Definition of dull 
