1. Impaired by diminution
   "The lessened impact of the scandal surprised everyone";
   - diminished, vitiated, weakened
    
2. Decreased in severity; made less harsh
   "The lessened restrictions allowed for more freedom of movement"

1. Become reduced in amount, level, intensity, or value
   "The amount of homework lessened towards the end of the semester";
   - decrease, diminish, fall, come down, go down, sink, dent
    
2. Make become smaller
   "The distance lessened between the two cars";
   - decrease, minify
    
3. Wear off or die down
   "The pain lessened";
   - subside

See also: impaired, mitigated

Type of: alter, change, change magnitude, modify, weaken

Encyclopedia: Lessen