'unhygienic' originates from the prefix 'un-' meaning 'not' and the word 'hygienic', which comes from the Greek word 'hygieinos', meaning 'healthful'.

'hygienic' evolved from the Greek word 'hygieinos', through Latin 'hygienicus', and eventually became the modern English word 'hygienic'. The prefix 'un-' was added to form 'unhygienic'.

Initially, 'hygienic' meant 'healthful', and with the prefix 'un-', it evolved to mean 'not healthful or clean'.