'unstainable' originates from the prefix 'un-' meaning 'not' and the word 'stain,' which comes from Old Norse 'steina,' meaning 'to paint.'

'stain' changed from the Old Norse word 'steina' and eventually became the modern English word 'stain.'

Initially, 'stain' meant 'to paint or color,' but over time it evolved to mean 'to mark or soil.'