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1. So lacking in interest as to cause mental weariness
   "the deadening effect of some routine tasks";
   - boring, dull, ho-hum [informal], irksome, slow, tedious, tiresome, wearisome, unamusing, deadly [informal], draggy [informal], mind-numbing

1. The act of making something futile and useless (as by routine)
   - stultification, constipation, impairment

1. Make vague, obscure or make (an image) less visible
   - dampen, damp
    
2. Cut a girdle around so as to kill by interrupting the circulation of water and nutrients
   - girdle
    
3. Make vapid or deprive of spirit
   "deadened wine"
    
4. Lessen the momentum or velocity of
   "deaden a ship's headway"
    
5. Become lifeless, less lively, intense, or active; lose life, force, or vigour
    
6. Make less lively, intense, or vigorous; impair in vigour, force, activity, or sensation
   "deaden a sound";
   - blunt
    
7. (chemistry) convert (metallic mercury) into a grey powder consisting of minute globules, as by shaking with chalk or fatty oil

Derived forms: deadenings

See also: lame, lameo [informal], meh [informal], samey [Brit, informal], uninspiring, uninteresting

Type of: alter, break, change, convert, damp, dampen, debasement, degradation, incise, modify, retard, soften, weaken

Antonym: liven