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
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Some women may notice physical symptoms like hot flashes first, while others notice cognitive symptoms like brain fog and mood swings.
—
Helen Carefoot, Flow Space, 11 Sep. 2025
Fatigue, brain fog, dysautonomia, shortness of breath, even months after infection.
—Kaif Shaikh, Interesting Engineering, 11 Sep. 2025
In 2020, she was diagnosed with Lyme disease after months of debilitating fatigue, brain fog, and memory loss.
—Stephan Rabimov, Forbes.com, 2 Sep. 2025
This prevents some of the complications that arise with outside opioid medications, including constipation, brain fog, slowed breathing, nausea, and drug tolerance and dependence.
—Dr. Sanjay Gupta, CNN Money, 26 Aug. 2025
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Helen Carefoot, Flow Space, 11 Sep. 2025
Fatigue, brain fog, dysautonomia, shortness of breath, even months after infection.
—Kaif Shaikh, Interesting Engineering, 11 Sep. 2025
In 2020, she was diagnosed with Lyme disease after months of debilitating fatigue, brain fog, and memory loss.
—Stephan Rabimov, Forbes.com, 2 Sep. 2025
This prevents some of the complications that arise with outside opioid medications, including constipation, brain fog, slowed breathing, nausea, and drug tolerance and dependence.
—Dr. Sanjay Gupta, CNN Money, 26 Aug. 2025
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 13 Sep. 2025.
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?
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