'unfiltered' originates from the prefix 'un-' meaning 'not' and the word 'filtered', which comes from the Latin 'filtrum', meaning 'felt used as a filter'.

'filtered' changed from the Latin word 'filtrum' and eventually became the modern English word 'filter'.

Initially, 'filter' meant 'to pass through a filter', but over time it evolved to include the meaning of 'removing impurities'.