Full of light; shining. See Synonyms at bright. Relating to or being a hue that has a combination of high lightness and strong saturation. Sharp and clear in tone. Glorious; magnificent: the brilliant court life at Versailles. Superb; wonderful: The soloist gave a brilliant performance. Marked by unusual and impressive intellectual acuteness: a brilliant mind; a brilliant solution to the problem. See Synonyms at intelligent. A precious gem, especially a diamond, finely cut in any of various forms with numerous facets.