'halfhearted' originates from Middle English, specifically the word 'half' meaning 'partly' and 'hearted' meaning 'with spirit or courage'.

'halfhearted' changed from the Middle English word 'halfherte' and eventually became the modern English word 'halfhearted'.

Initially, it meant 'partly spirited or courageous', but over time it evolved into its current meaning of 'lacking enthusiasm or interest'.