- splendid 1620s, probably a shortening of earlier splendidious (early 15c.), from L. splendidus "magnificent, brilliant," from splendere "be bright, shine, gleam, glisten," from PIE * (s)plend- "bright" (cf, Lith. splendziu "I shine," M.Ir. lainn "bright"). An earlier form was splendent (late 15c.).
Etymology dictionary. 2014.