Available Definitions:
1) a. - To make bright or brighter; to make to shine; to increase the luster of; to give a brighter hue to.
2) a. - To make illustrious, or more distinguished; to add luster or splendor to.
3) a. - 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.
4) a. - To make acute or witty; to enliven.
5) v. i. - To grow bright, or more bright; to become less dark or gloomy; to clear up; to become bright or cheerful.