lighten : Idioms & Phrases

• verb make more cheerful
  lighten; buoy up.
  
  • the conversation lightened me up a bit
• verb become more cheerful
  lighten; buoy up.
  
  • after a glass of wine, he lightened up a bit
• verb make lighter or brighter
  lighten; brighten.
  
  • The paint will brighten the room
• verb become lighter
  lighten.
  
  • The room lightened up

WordNet