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Synonyms

brainless

American  
[breyn-lis] / ˈbreɪn lɪs /

adjective

  1. mentally weak; foolish; witless; stupid.

brainless British  
/ ˈbreɪnlɪs /

adjective

  1. stupid or foolish

"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

Other Word Forms

  • brainlessly adverb
  • brainlessness noun

Etymology

Origin of brainless

First recorded in 1400–50, brainless is from the late Middle English word braynles. See brain, -less

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.

Wolff said after the race that the comments were "brainless".

From BBC • Dec. 1, 2025

In the aftermath, England was slammed as "brainless" and even "arrogant" by former greats for their meek performance after putting themselves in a strong position to win.

From Barron's • Nov. 29, 2025

Meme coins spawned on sites like Pump.fun, where the awful and the brainless alike became speculative fodder.

From The Wall Street Journal • Nov. 21, 2025

I'm not saying that bombast is automatically brainless.

From Salon • Apr. 28, 2025

“But who cares, we’ve got what we needed —” “He is not a brainless git,” said Hermione shrilly as they half ran toward the library.

From "Harry Potter And The Chamber Of Secrets" by J. K. Rowling

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.