'preoccupied' originates from Latin, specifically the word 'praeoccupatus,' where 'prae-' meant 'before' and 'occupare' meant 'to seize.'

'praeoccupatus' transformed into the French word 'préoccupé,' and eventually became the modern English word 'preoccupied' through Middle English.

Initially, it meant 'to seize beforehand,' but over time it evolved into its current meaning of 'engrossed in thought.'