'ultra-heterodox' is formed from the prefix 'ultra-' and the adjective 'heterodox.' 'ultra-' originates from Latin 'ultra,' meaning 'beyond' or 'on the other side,' and 'heterodox' ultimately comes from Greek 'heterodoxos' (hetero- 'other' + doxa 'opinion').

'heterodox' comes from Greek 'heterodoxos' (ἑτεροδόξος), passed into Late Latin as 'heterodoxus' and then into English via Middle French or directly from Latin; 'ultra-' has been used as a combining prefix in English since the 17th–18th centuries to intensify or mean 'beyond.' The compound 'ultra-heterodox' is a modern English formation using that prefix plus 'heterodox.'

Initially, elements meant 'beyond' (ultra-) and 'other opinion' (heterodox); combined, they have come to mean 'beyond merely unorthodox' — i.e., 'extremely unorthodox' or 'radically contrary to accepted doctrines.'