'half-heartedly' originates from the combination of 'half' and 'hearted,' where 'half' meant 'partially' and 'hearted' referred to 'having heart or enthusiasm.'

'half-hearted' changed from the Old English word 'heorte' meaning 'heart' and eventually became the modern English word 'half-heartedly.'

Initially, it meant 'with partial enthusiasm,' and this meaning has largely remained the same in modern usage.