IPA: /ˌɛks.kəˌmjun.ɪˈkeɪ.ʃən/
KK: /ˌɛkskəˌmjunɪˈkeɪʃən/
A formal punishment by a church that removes a person's membership and rights within that church.
After the scandal, the priest faced excommunication from the church.
Excommunication → It is formed from "ex-" (meaning out of or from) and "communicare" (meaning to share or to make common). The word refers to the act of excluding someone from participation in the community, particularly in a religious context.
Think of being 'excluded' ('ex-') from the 'community' ('communicare') — that's why excommunication means being cast out from a group.