brighten
v. B1 Intermediate US //ˈbɹaɪtən// UK //bɹˈaɪtən// bright·en
v. to make something more full of light or more colorful. You can also use it to describe someone becoming happier.
v. to make or become more luminous, light, or vivid in color; to cause an improvement in mood or outlook.
Fresh flowers always brighten the room.
The morning sun began to brighten the valley as the clouds finally cleared away.
While the new lighting was intended to brighten the workspace, the employees found that the sudden change in mood was actually due to the vibrant new wall art.
From bright + -en.
Usage
Can be used both transitively (to brighten something) and intransitively (the sky brightened). Often paired with the particle 'up' for emphasis.