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.
In addition to headaches, patients may experience ringing in the ears, vision disturbances, memory problems, brain fog, dizziness and nausea. Danielle Wilhour, The Conversation, 28 May 2025 There’s also emerging evidence creatine can help with medical conditions that cause fatigue, brain fog, and similar symptoms, including long COVID and chronic fatigue syndrome. Cindy Kuzma, SELF, 28 May 2025 My on/off symptoms of perimenopause have largely manifested as sleep deprivation, brain fog, and lack of focus and concentration. Devinder Bains, Glamour, 16 May 2025 That can be the experience that is called brain fog, and also hot flashes. Eric Rosenbaum, CNBC, 29 Apr. 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

Browse Nearby Words

Cite this Entry

“Brain fog.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brain%20fog. Accessed 10 Jun. 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)
Last Updated: - Updated example sentences
Love words? Need even more definitions?

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