make or become more light: [no object]:most of the country should brighten up later [with object]:the fire began to blaze fiercely, brightening the room
[with object] make (something) more attractively colourful:daffodils brighten up many gardens and parks
make or become happier and more cheerful: [no object]:Sarah brightened up considerably as she thought of Emily’s words [with object]:she seems to brighten his life
