'stalker' originates from Old English, specifically the word 'stælcan,' where 'stæl-' meant 'to go stealthily.'

'stælcan' transformed into the Middle English word 'stalken,' and eventually became the modern English word 'stalk' and its derivative 'stalker.'

Initially, it meant 'to move stealthily,' but over time it evolved into its current meaning of 'a person who follows or observes another.'