'heartless' originates from Old English, specifically the word 'heortleas,' where 'heorte' meant 'heart' and '-leas' meant 'without.'

'heortleas' transformed into the Middle English word 'herteles,' and eventually became the modern English word 'heartless.'

Initially, it meant 'without a heart or spirit,' but over time it evolved into its current meaning of 'lacking compassion or empathy.'