The story
- Proto-Germanic*slēpaz
- Proto-West Germanic*slāp
- Proto-West Germanic*slāpag
- Old English*slǣpiġ
- Middle Englishslepy
- Englishsleepyclip.
- English todayeepy
Clipping of sleepy. The term was initially popularized by an Internet meme of a sleepy cat with the caption "and why he eepy?", which first appeared in late 2021. The word rapidly increased in popularity from late 2022 through 2023.
Etymology from Wiktionary, CC BY-SA 4.0.