lighten_up
1. [ verb ] make lighter or brighter
Synonyms: brighten lighten
Examples:

"The paint will brighten the room"

Related terms: darken change brighten
2. [ verb ] become lighter
Synonyms: lighten
Examples:

"The room lightened up"

Related terms: change light irradiate
Similar spelling:   lighten
  lightning_bug
  lightening
  lighting-up
  listen_in
  lightning_rod
  lightning
  lichtenstein
  light_unit
  light_time