What is the meaning of deadening?

noun

• The act of making something futile and useless (as by routine.
  • synonyms: stultification, constipation, impairment

verb

• Make vague or obscure or make (an image) less visible.
  • usage: "muffle the message"
  • synonyms: dampen, deaden, damp
• Cut a girdle around so as to kill by interrupting the circulation of water and nutrients.
  • usage: "girdle the plant"
  • synonyms: girdle, deaden
• Make vapid or deprive of spirit.
  • usage: "deadened wine"
  • synonyms: deaden
• Lessen the momentum or velocity of.
  • usage: "deaden a ship's headway"
  • synonyms: deaden
• Become lifeless, less lively, intense, or active; lose life, force, or vigor.
  • synonyms: deaden
• Make less lively, intense, or vigorous; impair in vigor, force, activity, or sensation.
  • usage: "Terror blunted her feelings"; "deaden a sound"
  • synonyms: deaden, blunt
• Convert (metallic mercury) into a grey powder consisting of minute globules, as by shaking with chalk or fatty oil.
  • synonyms: deaden

adjective

• 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, dull, ho-hum, irksome, slow, tedious, tiresome, wearisome