How do you describe someone who is into incest?

Solution 1:

Incestuous (adj): (the noun is incestuousnesses)

  • adj. Of, involving, or suggestive of incest.
  • having committed incest.
  • Someone who commits incest is the more common way to refer to an incestuous person.

A less common term is incestophile according to Wikipedia:

  • A person who engages in incest is called an incestophile.