'unorthodoxy' originates from the prefix 'un-' meaning 'not' and the Greek word 'orthodoxos', where 'orthos' meant 'right' and 'doxa' meant 'opinion'.

'orthodoxos' transformed into the Medieval Latin word 'orthodoxia', and eventually became the modern English word 'orthodoxy', with 'un-' added to form 'unorthodoxy'.

Initially, it meant 'not conforming to established doctrine', and this meaning has largely remained the same in modern usage.