brain fog

brain fog (uncountable)

1. (informal) A mental condition in which the subject experiences problems in concentrating, thinking clearly, or remembering things; a sense of not being completely awake or mentally acute.

   Synonyms: cog fog, obnubilation

   Coordinate term: brain cloud

   • 1886, Mary Jane Holmes, Bessie's Fortune, G. W. Carleton & Co., page 261:

     Then, as the brain fog lifted a little and cleared away, his chin quivered and he went on : “ Oh, Daisy, Daisy ; it comes back to me now, the years that are gone, and you as you were then. ”

   • 1899, Mary H. Hunt, contribution to the discussion session on a lecture by W.O. Atwater, “Alcohol physiology and superintendence”. Proceedings of the Department of Superintendence, National Educational Association, page 82:

     That woman and her question must have emanated from the brain fog of some opposer to scientific temperance education who was trying to find out for himself whether three glasses of whisky or a bottle of Rhine wine is isodynamic with certain amounts of sugar, fat, and starch.

   • 2018, Carolyn de Lorenzo, “The Scientific Reason You’re So Brain Foggy Over The Summer”, in Bustle‎:

     While the warm, lingering days of summer are doubtless a wonderful thing, the brain fog that can accompany surging temperatures is actually real — and it doesn’t feel so wonderful.

   • 2020 October 11, Pam Belluck, “‘I Feel Like I Have Dementia’: Brain Fog Plagues Covid Survivors”, in New York Times‎:

     It’s becoming known as Covid brain fog: troubling cognitive symptoms that can include memory loss, confusion, difficulty focusing, dizziness and grasping for everyday words. Increasingly, Covid survivors say brain fog is impairing their ability to work and function normally.

• Not to be confused with brain fag.