IN'CEST, noun [Latin incestum; in and castus, chaste.] The crime of cohabitation or sexual commerce between persons related within the degrees wherein marriage is prohibited by the law of a country. Spiritual incest is a like crime committed between persons who have a spiritual alliance by means of baptism or confirmation. It is also understood of a vicar or other beneficiary, who holds two benefices, the one depending on the collation of the other.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI