brain fog

American

[breyn fog, fawg] / ˈbreɪn ˌfɒg, ˌfɔg /

Also brain-fog,

noun

a mental state marked by difficulty remembering, concentrating, or thinking clearly, often caused by exhaustion, stress, or illness: For new parents, fatigue and brain fog seem inevitable.

He had so much brain fog that a single thought felt impossible.
For new parents, fatigue and brain fog seem inevitable.
Research has found that long COVID can cause brain fog and memory loss.

Etymology

Origin of brain fog

First recorded in 1850–55; brain ( def. ) + fog ¹ ( def. )

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Tessa Gonzalez, a 51-year-old from Stockton, Calif., said her primary care provider told her symptoms of brain fog and inconsistent sleep were normal for perimenopause.

From The Wall Street Journal

"Your mental health is affected. You get brain fog, you're tired, you're fatigued. You can't function as a woman – and that's every day for 10 years," she said.

From BBC

She is also calling for more support in the workplace, highlighting how brain fog, anxiety and insomnia are the top three symptoms which affect women at work.

From BBC

Barbieri said brain fog, another menopause symptom, can also be a sign of early onset dementia, although that is rare.

From The Wall Street Journal

He said the concussion triggered his language difficulties and caused him to endure flashbacks, anxiety, and brain fog after the incident.

From BBC

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023