brain fog

noun

: a usually temporary state of diminished mental capacity marked by inability to concentrate or to think or reason clearly

Examples of brain fog in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Difficulty Concentrating Pregnancy can sometimes cause brain fog due to hormonal changes. Andrea L. Braden, Verywell Health, 12 Mar. 2025 While the primary treatment targets the root cause of brain fog, several lifestyle approaches can help manage its symptoms. Dominique Fluker, Essence, 10 Mar. 2025 People experiencing brain fog often talk about poor attention span, feeling drained, confused, and having difficulty remembering things. Lorena O'Neil, Rolling Stone, 9 Mar. 2025 For centuries, thyroid dysfunction was endemic; millions of people around the world suffered from slow heartbeats, weakness, muscle fatigue, sluggish metabolism, and brain fog. Ellen Cushing, The Atlantic, 8 Mar. 2025 See All Example Sentences for brain fog

Word History

First Known Use

1853, in the meaning defined above

Time Traveler
The first known use of brain fog was in 1853

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Cite this Entry

“Brain fog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brain%20fog. Accessed 25 Mar. 2025.

Medical Definition

brain fog

noun
: a usually temporary state of diminished mental capacity marked by inability to concentrate or to think or reason clearly
This brain fog can be a result of being overly stressed, tired, carrying extra weight, consuming too many calories or consistently consuming a diet poor in nutrients.Kylie Helgens, The Gazette (Cedar Rapids, Iowa)
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