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brainiac

American  
[brey-nee-ak] / ˈbreɪ niˌæk /

noun

  1. a highly intelligent person.


brainiac British  
/ ˈbreɪnɪˌæk /

noun

  1. informal a highly intelligent person

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of brainiac

From Brainiac, a superintelligent, villainous alien in the Superman comics, probably brain + (man)iac

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Living up to his reputation as Cahiers’ brainiac bad boy, he pockets the office’s petty cash to road-trip to the Cannes premiere of Truffaut’s “The 400 Blows.”

From Los Angeles Times • Oct. 29, 2025

Revolori's amiable turn as the band's well-read brainiac keeps a group that primarily depends on edged weapons and acrobatics connected to its large-heartedness.

From Salon • Nov. 30, 2022

Now settled in the fictitious Port Oswego, Ore., the congenial brainiac has become popular among students and teachers alike.

From New York Times • Jan. 11, 2022

“The Big Bang Theory” star and real-life brainiac Mayim Bialik also got lots of positive reviews, as did former “Jeopardy!” champion Buzzy Cohen.

From Seattle Times • Aug. 9, 2021

Jason finally gets along with Annabeth, and her brainiac tendencies start rubbing off on him.

From "The Mark of Athena" by Rick Riordan

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