'unorthodox' originates from Greek, specifically the word 'orthodoxos,' where 'orthos' meant 'right' and 'doxa' meant 'opinion.'

'orthodoxos' transformed into the Late Latin word 'orthodoxus,' and eventually became the modern English word 'orthodox,' with 'un-' added to denote the opposite.

Initially, it meant 'not conforming to established doctrine,' but over time it evolved into its current meaning of 'not conforming to what is usual or traditional.'