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

Our body’s flucutations naturally put us off guard, so every day pressures can feel magnified and trigger a cascase of both physical and mental tolls that amplifiy sleep disruptions, worsen brain fog, accelerate weight gain and spike stress. — Cheryl Fenton, Flow Space, 23 Sep. 2026

Symptoms With More Than One Cause Fatigue, weight gain, brain fog, and low libido often get pinned on testosterone first. — Malana Vantyler, USA Today, 10 Sep. 2026

Watch for the dehydration symptoms Alfano flags, including constipation, low energy, brain fog, headaches and dry skin, and the more serious complications Martorano cites, including kidney stones and urinary tract infections. — Hanna Wickes, Charlotte Observer, 8 Sep. 2026

Somedays her brain fog, headaches and blood pressure would be so bad, her mom needed to pick her up from school. — Maggie Menderski, Louisville Courier Journal, 28 Aug. 2026

Word History

First Known Use

1853, in the meaning defined above

Rhymes for brain fog

• agog
• backlog
• bulldog
• bullfrog
• eclogue
• eggnog
• groundhog
• hedgehog
• leapfrog
• prolog
• sheepdog
• watchdog

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)