Resplendent has a lot in common with splendid (meaning, among other things, "shining" or "brilliant"), splendent ("shining" or "glossy"), and splendor ("brightness" or "luster"). Each of these glowing terms gets its shine from the Latin verb splendēre ("to shine"). In the case of resplendent, the prefix re- added to splendēre, formed the Latin resplendēre, meaning "to shine back." Splendent, splendor, and resplendent were first used in English during the 15th century, but splendid didn't light up our language until over 175 years later; its earliest known use dates from the early 1600s.