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.
No, a girl needs that for brain fog. Samantha Agate, Miami Herald, 17 June 2026 The Link Between Hot Flashes and Memory Many women going through menopause report brain fog, forgetfulness and difficulty concentrating. Lauryn Higgins, Flow Space, 17 June 2026 The underlying songwriting is impulsive, but many tracks adopt a deliberately sedate mood or sort through dense clusters of cut-up loops, and Alfa’s spatialization gives the album a pallor that can resemble brain fog. H.d. Angel, Pitchfork, 16 June 2026 Millions of women are walking into doctors’ offices with fatigue, anxiety and brain fog and walking out with a thyroid prescription or an antidepressant. Allison Palmer updated June 13, Sacbee.com, 13 June 2026 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

Browse Nearby Words

Cite this Entry

“Brain fog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brain%20fog. Accessed 19 Jun. 2026.

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)
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster