sundowning

noun

sun·​down·​ing ˈsən-ˌdau̇-niŋ How to pronounce sundowning (audio)
: a state of increased agitation, confusion, disorientation, and anxiety that typically occurs in the late afternoon or evening in some individuals affected with dementia
Shorter days during winter months can increase the risk of "sundowning." Monitor closely for agitation or restlessness as day transitions into night.Marisa Korytko
Sundowning affects up to two-thirds of patients with dementia, and it may be a sign that the disease is progressing.Patti Thummel

Word History

Etymology

sundown + -ing entry 1, after earlier sundowner syndrome in same sense

First Known Use

1978, in the meaning defined above

Time Traveler
The first known use of sundowning was in 1978

Browse Nearby Words

Cite this Entry

“Sundowning.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sundowning. Accessed 18 Mar. 2026.

Medical Definition

sundowning

noun
sun·​down·​ing ˈsən-ˌdau̇n-iŋ How to pronounce sundowning (audio)
: a state of increased agitation, confusion, disorientation, and anxiety that typically occurs in the late afternoon or evening in some individuals affected with dementia
Sundowning is a major problem in the middle and late stages of disorders, such as Alzheimer's disease, that cause dementia.Patricia N. Prinz et al., The New England Journal of Medicine
Last Updated: - Entry added
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