brilliancy

US: /ˈbrɪljənsi/ ,(bril′yən sē)

WordReference Random House Learner's Dictionary of American English © 2026

bril•lian•cy /ˈbrɪlyənsi/   n. [uncountable]

1. brilliance.

WordReference Random House Unabridged Dictionary of American English © 2026

bril•lian•cy  (bril′yən sē), n., pl. -cies for 1.

1. an instance of brilliance:
   the brilliancies of Congreve's wit.
2. brilliance.

• brilli(ant) + -ancy 1740–50

WordReference Random House Learner's Dictionary of American English © 2026

bril•liance /ˈbrɪlyəns/   n. [uncountable]

1. the state or quality of being brilliant:
   The huge diamond glowed with brilliance.

WordReference Random House Unabridged Dictionary of American English © 2026

bril•liance  (bril′yəns), n. 

1. great brightness;
   luster:
   the brilliance of a fine diamond.
2. excellence or distinction;
   conspicuous talent, mental ability, etc.
3. splendor, elegance, or magnificence:
   the brilliance of the court of Louis XIV.
4. Optics that luminance of a body consisting of its saturation and brightness.

• brilli(ant) + -ance 1745–55

Synonyms

• 1. . radiance, effulgence, refulgence.
• 2. . illustriousness, preeminence; genius.

Antonyms

• 1, 2. . dullness.

Collins Concise English Dictionary © HarperCollins Publishers::

brilliance / ˈbrɪljəns/, brilliancy noun

1. great brightness; radiance
2. excellence or distinction in physical or mental ability; exceptional talent
3. splendour; magnificence
4. a former term for luminance