'shady' originates from Old English, specifically the word 'sceadu,' where 'sceadu' meant 'shade or shadow.'

'sceadu' transformed into the Middle English word 'schadwe,' and eventually became the modern English word 'shade' and its derivative 'shady.'

Initially, it meant 'shade or shadow,' but over time it evolved into its current meaning of 'providing shade or being suspicious.'