exclude from a church or a religious community; "The gay priest was excommunicated when he married his partner"
oust or exclude from a group or membership by decree
the punishment of cutting off a person from receiving the sacraments and exclusion from the communion of the church.
The word communicate originally meant to take Communion. People who are excommunicated are barred from Communion for disciplinary reasons, but may still participate in other parts of the service.
To exclude, by an act of ecclesiastical authority, from the sacriments, rights, and priveleges of a church