'impractical' originates from the prefix 'im-' meaning 'not' and the word 'practical', which comes from the Latin 'practicus', meaning 'fit for action'.

'practicus' transformed into the Old French word 'practique', and eventually became the modern English word 'practical', with 'impractical' being formed by adding the prefix 'im-'.

Initially, 'practicus' meant 'fit for action', but 'impractical' evolved to mean 'not fit for action or use'.