'sleepy' originates from Old English, specifically the word 'slǣpīg,' where 'slǣp' meant 'sleep.'

'slǣpīg' transformed into the Middle English word 'slepī,' and eventually became the modern English word 'sleepy.'

Initially, it meant 'full of sleep,' but over time it evolved into its current meaning of 'feeling drowsy or ready to fall asleep.'