diet incest

Being an adopted child of no blood relation to one's adopted parents, the act of having sex with a relative. It has all the flavor of incest without the incest, technically since there is no close biological link between the two (or more) individuals partaking in the act.

Mike: Hey, Nick, did you hear Brian fucked his older sister?

Nick: Awww, gross, dude!? What the fuck?

Mike: I know, but technically they're not related. Brian is adopted; so, it was diet incest.

by jmw87 October 1, 2010

Incest-in-law

To fuck one's brother-in law or sister-in-law.

Ed: "Wait, Jack fucked his wife Jill's sister?"
Eddie: "Yeah he just committed incest-in-law."

by The Elias June 2, 2016

Incest expert

Synonym: Pornstar

Person 1: Whoa.. why is he so in love with his cousins?
Person 2: That’s just Pornstar, he’s an incest expert, straight from Alabama.

by Python3 July 28, 2019

Incest Evan

A person named Evan who dated his cousin and kissed that bitch like bro thats kinda weird.

Hey, that dude fucked his sister, we should call him incest evan

by Lil Carrotcake November 6, 2018

program incest

Having intimate relations with someone within your college or university program. Often risking a break up and hardships throughout the rest of your post-secondary experience, generally frowned upon especially in smaller program sizes.

Joe: Hey, that girl in our lecture is hot AF.
Greg: No that'd be program incest, you know you never do that.

by bean george May 27, 2021

soft incest

Relations with a family member who shares no blood relation, e.g. related by marriage or adoption.

She engaged in some soft incest with her former stepbrother.

by jharrison3452 December 31, 2015

incest belt

The group of southern states reaching from Texas to Georgia.

My cousins are from The Incest Belt, so you know they're sleeping with each other.

by ap3419 November 30, 2013