'excommunicate' originates from Late Latin, specifically the word 'excommunicare', where 'ex-' meant 'out of' and 'communicare' meant 'to make common' (from Latin 'communis' meaning 'common').

'excommunicate' changed from Medieval/Church Latin 'excommunicare' and passed into Old French as 'excommunier' before entering Middle English (forms such as 'excommunicen'/'excommunicate'), eventually becoming the modern English 'excommunicate'.

Initially it meant 'to put out of communion (exclude from common fellowship of the church)'; over time it has retained that primary ecclesiastical sense while also extending to secular senses of formal exclusion from organizations or communities.