'unmixable' originates from the prefix 'un-' meaning 'not' and the root word 'mix,' which comes from Latin 'miscere,' meaning 'to mix.'

'unmixable' changed from the Old English word 'miscian' and eventually became the modern English word 'mix' with the prefix 'un-' added to denote the negative form.

Initially, it meant 'not able to be mixed,' and this meaning has largely remained the same in modern usage.