What is the meaning of dull?

verb

• Make dull in appearance.
  • usage: "Age had dulled the surface"
• Become dull or lusterless in appearance; lose shine or brightness.
  • usage: "the varnished table top dulled with time"
• Deaden (a sound or noise), especially by wrapping.
  • synonyms: muffle, mute, damp, dampen, tone down
• Make numb or insensitive.
  • usage: "The shock numbed her senses"
  • synonyms: numb, benumb, blunt
• Make dull or blunt.
  • usage: "Too much cutting dulls the knife's edge"
  • synonyms: blunt
• Become less interesting or attractive.
  • synonyms: pall
• Make less lively or vigorous.
  • usage: "Middle age dulled her appetite for travel"

adjective

• Lacking in liveliness or animation.
  • usage: "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"
• Emitting or reflecting very little light.
  • usage: "a dull glow"; "dull silver badly in need of a polish"; "a dull sky"
• Being or made softer or less loud or clear.
  • usage: "the dull boom of distant breaking waves"; "muffled drums"; "the muffled noises of the street"; "muted trumpets"
  • synonyms: muffled, muted, softened
• So lacking in interest as to cause mental weariness.
  • usage: "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"
  • synonyms: boring, deadening, ho-hum, irksome, slow, tedious, tiresome, wearisome
• Of color. ( very low in saturation; highly diluted)
  • usage: "dull greens and blues"
• Not keenly felt.
  • usage: "a dull throbbing"; "dull pain"
• Slow to learn or understand; lacking intellectual acuity.
  • usage: "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"
  • synonyms: dense, dim, dumb, obtuse, slow
• Of business. ( not active or brisk)
  • usage: "business is dull (or slow)"; "a sluggish market"
  • synonyms: slow, sluggish
• Not having a sharp edge or point.
  • usage: "the knife was too dull to be of any use"
• Blunted in responsiveness or sensibility. "a dull gaze"; "so exhausted she was dull to what went on about her- Willa Cather
• Not clear and resonant; sounding as if striking with or against something relatively soft.
  • usage: "the dull thud"; "thudding bullets"
  • synonyms: thudding
• Darkened with overcast.
  • usage: "a dark day"; "a dull sky"; "the sky was leaden and thick"
  • synonyms: leaden