'guiltless' originates from Old English, specifically the word 'gyltlēas', where 'gylt' meant 'offense' and '-lēas' meant 'without'.

'gyltlēas' changed from Old English to Middle English as 'giltles', and eventually became the modern English word 'guiltless'.

Initially, it meant 'without offense', and this meaning has largely remained the same in modern usage.