Superlative form of drowsy; most sleepy or the most inclined to drowse among all things being compared.
From drowsy plus -est (superlative adjective marker, used for comparisons among three or more items).
The time of day most people are drowsiest is the 'post-lunch dip'—a predictable biological phenomenon that humans across cultures have combat with napping traditions, from siestas to tea time!
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