Incest is defined as “sexual relations between people classified as being too closely related to mary each other.”

According to the late Whitney Houston’s mother, Cissy Houston, Whitney’s daughter, Bobbi Kristina, 19, and her fiance, Nick Gordon, 22, are involved in an incestuous relationship.

But are Bobbi K. and Nick even blood relatives? No, according to Nick who tweeted that he and Bobbi K. “got a little closer” after Whitney died.

Whitney reportedly moved Nick into her home when he was only 12, and his mother was unable to care for him. Sometime after that, Bobbi K. and Nick, who referred to each other as “brother” and “sister” began getting to know each other more intimately.

On Wednesday, Nick told ABCNews.com that the two are “just close – and going through her mom’s passing and grieving together.”

But TMZ.com has photos and videos of Bobbi K. and Nick tonguing each other down outside a Duluth, Georgia Target store near Bobbi’s home in Alpharetta, a suburb north of Atlanta.

Cissy, who tried to break the kids up once before, wants the relationship to end.

According to TMZ, Cissy told a friend, “What they’re doing is incestuous,” in response to the video. Cissy is reportedly afraid that Nick is a bad influence on Bobbi Kristina, who she says is particularly vulnerable right now following her mother’s death, and she wants him out. Cissy has filed paperwork to have Nick evicted, according to TMZ.com.

It’s obvious that Nick has no plans to ever work for a living, and Bobbi K. is his meal ticket.

Source: NYDN