'unadoptable' originates from the prefix 'un-' meaning 'not' and the word 'adoptable', which comes from 'adopt'.

'adoptable' changed from the Latin word 'adoptare', meaning 'to choose for oneself', and eventually became the modern English word 'adopt'.

Initially, 'adopt' meant 'to choose for oneself', but over time it evolved into its current meaning of 'to legally take another's child and bring it up as one's own'.