effulgent (adj.)

1738, back-formation from effulgence, or else from Latin effulgentem (nominative effulgens), present participle of effulgere "to shine out, gleam forth," from assimilated form of ex "out" (see ex-) + fulgere "to shine" (from PIE *bhleg- "to shine, flash," from root *bhel- (1) "to shine, flash, burn"). Related: Effulgently.