Emily Dickinson Lexicon

BRILL'IANT, a. [Fr. brilliant, sparkling, from briller, to shine or sparkle; It. brillante, sparkling; brillo, joy, gladness, also tipsey; Sp. brillar, to glitter; brillador, brilliant; brillo, splendor; Ger. and Dan. brille, a pair of spectacles; hence Eng. beryl and pearl.]

1. Sparkling with luster; glittering; as, a brilliant gem; a brilliant dress.
2. Splendid; shining; as, a brilliant achievement. Washington was more solicitous to avoid fatal mistakes, than to perform brilliant exploits. – Ames.