'purplish' is formed in English by adding the suffix '-ish' to the word 'purple', where '-ish' means 'somewhat' or 'like'.

'Purple' comes from Old English 'purpul', from Latin 'purpura', and the suffix '-ish' is from Old English '-isc', used to form adjectives meaning 'belonging to' or 'having the nature of'.

Initially, it meant 'somewhat purple', and this meaning has remained unchanged in modern usage.