2. To make illustrious, or more distinguished; to add luster or splendor to. The present queen would brighten her character, if she would exert her authority to instill virtues into her people. (Swift)
3. To improve or relieve by dispelling gloom or removing that which obscures and darkens; to shed light upon; to make cheerful; as, to brighten one's prospects. An ecstasy, which mothers only feel, Plays round my heart and brightens all my sorrow. (Philips)
Origin: From bright.