'antitraditionally' originates from English, specifically the prefix 'anti-' (from Greek 'antí') meaning 'against' combined with 'traditional' (from Latin 'traditio' via Old French), where 'traditio' meant 'a handing over, tradition'.

'antitraditionally' developed from the adjective 'antitraditional' (formed by prefixing 'anti-' to 'traditional'), with 'traditional' itself coming from Latin 'traditio' -> Old French 'tradicion' -> Middle English 'tradicioun' and later modern English 'tradition' + adjectival suffix '-al' and adverbial suffix '-ly'.

Initially, elements meant 'against' (anti-) and 'handing over/what is handed down' (traditio); over time the combined word came to mean 'in a way that opposes or rejects tradition', which is its current usage.