illustrissimeadjectiveSyllable DecompositionillustrissimeEtymologyexpandderived from illustrious with the superlative suffix -issime.Definitions1. Which is very illustrious.expand2. Title given by honor to some people of high dignity, and mainly to certain ecclesiastics, especially the cardinals until the 16th century.in particularexpandIllustrissime, et révérendissime seigneur.PluralillustrissimesSee alsoillustre (adj.)