unchurch means to expel from membership of a congregation or church; to excommunicate. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Why “unchurch” is a great word
UNCHURCH — [Verb] To expel from membership of a congregation or church. Formed within English from the prefix un- (expressing reversal or deprivation) and the noun church. First recorded in use 1610–20. Unlike excommunicate (which denotes a formal, sacramental severance) or disfellowship (which implies a withdrawal of companionship), to unchurch is the blunt revocation of spiritual belonging itself. It is the conspicuous vacancy of a family pew, the averted gaze during the passing of the peace, the cold finality of a name struck from the parish roll—a quiet exile that renders sacred space merely physical.
Etymology
From un- + church.
verb
- To expel from membership of a congregation or church; to excommunicate.