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
Fatigue, mood changes, brain fog and sleep disruption overlap with multiple conditions.
—
Lauryn Higgins, Flow Space, 12 May 2026
Drinking excess caffeine, especially later in the day, can interfere with proper sleep, which can contribute to poor energy and brain fog, thus feeling even more dependent on coffee to get you through the day.
—Teresa Mull, FOXNews.com, 8 May 2026
Many of their patients suffer from migraines, nausea, wheezing, eye infections and brain fog.
—ABC News, 16 Apr. 2026
But eventually the symptoms stacked up, and the extreme exhaustion, fluid retention, and brain fog could no longer be ignored.
—Holly Carter, PEOPLE, 15 Apr. 2026
See All Example Sentences for brain fog
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.
Lauryn Higgins, Flow Space, 12 May 2026
Drinking excess caffeine, especially later in the day, can interfere with proper sleep, which can contribute to poor energy and brain fog, thus feeling even more dependent on coffee to get you through the day.
—Teresa Mull, FOXNews.com, 8 May 2026
Many of their patients suffer from migraines, nausea, wheezing, eye infections and brain fog.
—ABC News, 16 Apr. 2026
But eventually the symptoms stacked up, and the extreme exhaustion, fluid retention, and brain fog could no longer be ignored.
—Holly Carter, PEOPLE, 15 Apr. 2026
See All Example Sentences for brain fog
Cite this Entry
“Brain fog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brain%20fog. Accessed 21 May. 2026.
Copy CitationMedical 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)
Kylie Helgens, The Gazette (Cedar Rapids, Iowa)Love words? Need even more definitions?
Merriam-Webster unabridged
