sundown

noun

1. (US, countable, uncountable)Sunset.

   “We’ll meet by the pier at sundown.”

   “Yet oft when sundown skirts the moor ⁠An inner trouble I behold, ⁠A spectral doubt which makes me cold, That I shall be thy mate no more, […]”

2. (countable)A hat with a wide brim to shade the eyes from sunlight.

verb

1. (intransitive)to experience an episode or an onset of some detrimental mental condition like agitation, anxiety, hallucination or dementia, daily at the approach of nightfall.

   “"She also “sundowned”, and someone had to keep an eye on her 24-7."”