'reek' originates from Old English, specifically the word 'rēocan,' where 'rēocan' meant 'to emit smoke or vapor.'

'rēocan' transformed into the Middle English word 'reken,' and eventually became the modern English word 'reek.'

Initially, it meant 'to emit smoke or vapor,' but over time it evolved into its current meaning of 'to emit a strong, unpleasant smell.'