WordWeb Online

1. Make more cheerful
   "the conversation lightened me up a bit"
   - lighten up, buoy up
    
2. Reduce the weight on; make lighter
   "she lightened the load on the tired donkey"
    
3. Become more cheerful
   "after a glass of wine, he lightened up a bit"
   - lighten up, buoy up
    
4. Make lighter or brighter
   - brighten, lighten up
    
5. Become lighter
   "The room lightened up"
   - lighten up
    
6. Alleviate or remove (pressure or stress) or make less oppressive
   "lighten the burden of caring for her elderly parents"
   - relieve

Derived forms: lightened, lightens, lightening

Type of: alter, change, cheer, cheer up, chirk up, disburden, mitigate, modify, unburden

Antonym: darken, weigh down