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 commerce between persons
related within the degrees wherein marriage is prohibited by
law. Shak.
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.