1
: devoid of intelligence : stupid
a brainless decision
2
: not demanding understanding or intelligence : dull, stupefying
a brainless task
brainless repetition
3
: lacking a brain
brainless organisms
brainlessly
adverb
brainlessness
noun
Synonyms
- airheaded
- birdbrained
- bonehead
- boneheaded
- brain-dead
- bubbleheaded
- chuckleheaded
- dense
- dim
- dim-witted
- doltish
- dopey
- dopy
- dorky [slang]
- dull
- dumb
- dunderheaded
- empty-headed
- fatuous
- gormless [chiefly British]
- half-witted
- knuckleheaded
- lamebrain
- lamebrained
- lunkheaded
- mindless
- oafish
- obtuse
- opaque
- pinheaded
- senseless
- simple
- slow
- slow-witted
- soft
- softheaded
- stupid
- thick
- thick-witted
- thickheaded
- unintelligent
- unsmart
- vacuous
- weak-minded
- witless
Examples of brainless in a Sentence
He thought most of his coworkers were brainless.
The plot of the new movie is brainless and the acting is terrible.
Recent Examples on the Web
The O’Haras happen to move in next door to him.
Frothy and often filthy without being brainless (send thanks across the Atlantic for that good British dialogue), this is escapism done right.
—
Judy Berman, TIME, 30 Oct. 2024
So, what can the neuronal activity of a tiny, brainless creature possibly tell us about the evolution of our own complex brains?
—Elizabeth Rayne, Ars Technica, 15 June 2024
There's really no way to prep for the show — basically, just don't be brainless.
—Tanner Stransky, EW.com, 8 Apr. 2024
An oyster, immobile and nearly brainless, is hardly even an animal, despite what the taxonomists tell us.
—Peter Rubin, Longreads, 9 Jan. 2024
See all Example Sentences for brainless 
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Judy Berman, TIME, 30 Oct. 2024
So, what can the neuronal activity of a tiny, brainless creature possibly tell us about the evolution of our own complex brains?
—Elizabeth Rayne, Ars Technica, 15 June 2024
There's really no way to prep for the show — basically, just don't be brainless.
—Tanner Stransky, EW.com, 8 Apr. 2024
An oyster, immobile and nearly brainless, is hardly even an animal, despite what the taxonomists tell us.
—Peter Rubin, Longreads, 9 Jan. 2024
See all Example Sentences for brainless
Dictionary Entries Near brainless
Cite this Entry
“Brainless.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brainless. Accessed 26 Dec. 2024.
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