'Spiritual incest' definitions:

Definition of 'Spiritual incest'

From: GCIDE

Incest \In"cest\, n. [F. inceste, L. incestum unchastity, incest, fr. incestus unchaste; pref. in- not + castus chaste. See Chaste.] The crime of cohabitation or sexual intercourse between persons related within the degrees wherein marriage is prohibited by law; broadly, sexual relations between closely related persons, usually taken as first cousins or closer. --Shak. [1913 Webster +PJC]
Spiritual incest. (Eccl. Law) (a) The crime of cohabitation committed between persons who have a spiritual alliance by means of baptism or confirmation. (b) The act of a vicar, or other beneficiary, who holds two benefices, the one depending on the collation of the other. [1913 Webster]