'de-feudalisation' originates from Modern English, specifically the prefix 'de-' and the word 'feudalisation', where 'de-' meant 'removal' or 'reversal' and 'feudal' (via Medieval Latin 'feodum') related to a 'fief' or the feudal system.

'de-feudalisation' developed by combining the productive English prefix 'de-' with 'feudalisation'. 'Feudal' came into English from Old French/Medieval Latin (e.g. Medieval Latin 'feodalis' from 'feodum' meaning 'fief'), leading to 'feudal' and later the noun-forming '-isation' to create 'feudalisation', then prefixed to form 'de-feudalisation'.

Initially the root 'feodum' meant 'fief' or 'land held by vassal'; over time 'feudal' came to denote the broader social and political system, and 'de-feudalisation' acquired the modern meaning of 'removal or dismantling of feudal structures'.