'disagree' originates from Middle English, specifically the word 'disagreen', where the prefix 'dis-' meant 'not' and 'agreen' meant 'to be of the same mind'.

'disagree' changed from the Middle English word 'disagreen' and eventually became the modern English word 'disagree'.

Initially, it meant 'to fail to agree or to be of a different opinion', and over time it evolved into the current meaning 'to have or express a different opinion' (the core sense has been largely maintained).