brilliancy

noun

Etymology: From brilliant + -ancy; attested earlier than brilliance. Compare French brillance.

1. A shining quality; brilliance.

   “The beauty and brilliancy of this insect are indescribable, and none but a naturalist can understand the intense excitement I experienced when I at length captured it.”

   “[…] to assist greatly in the consumption of the lamp, and to diminish the aqueous precipitations produced on the interior of the lantern glass, which has the effect of reducing more or less the brilliancy of the light.”

2. An act of being brilliant.

   “His brilliancy lay in combining old concepts from far-flung fields into a new idea.”

   “Surely it must have been his brilliancy that accounted for Vardon standing out as a stroke or two better than such a model of steadiness as J. H. Taylor[.]”

3. A spectacular and beautiful game of chess, generally featuring sacrificial attacks and unexpected moves.

   “Bobby Fischer, one of the greatest chess players who ever lived, died at the age of sixty-four from kidney failure. He had lived one year for each square on a chessboard. / THE GOOD / First of all, you should learn the term “brilliancy.” It refers to a game that is played with spectacular strategy and beauty, typically featuring unexpected moves and ingenious ideas. In other words, the game is extraordinary! At age thirteen, Bobby Fischer won a brilliancy against twenty-six-year-old Donald Byrne.”