One picture can carry all of this: coming down. Sleep has not arrived yet, but it is pulling. The head dips, the page stops moving, sounds arrive a second late. From there the word can stay on the person who feels the pull, or move onto whatever is doing the pulling - a hot afternoon, a silent room, a of cough syrup.
可以想成一個畫面：眼皮正在往下掉。人還沒睡著，但睡意已經在拉了——頭一點一點的，書頁停在同一行，別人講話你慢半拍才聽懂。這個字可以停在「被拉的人」身上，也可以挪到「正在拉的東西」身上：悶熱的午後、安靜的房間、一匙糖漿，都可以接手這個字。
From the word’s history
Wiktionary records drowsy as drowse plus -y, and points to Old English drusian, to droop or become languid. The drooping is the same movement as the eyelid in the core image.
依 Wiktionary，drowsy 是 drowse（打瞌睡）加上 -y；它同時指出更早的古英語 drūsian 有「垂下、變得無力」的意思。那個「垂下」跟核心畫面裡眼皮往下掉是同一個動作。
Wiktionary (kaikki:3f6f69a190036ae4:638599329:34365), etymology_text supplied in this packet
登入就可以看每一支怎麼連回核心畫面。