Gonadnarel is a mafia. Usually related to the mafia party game. It is used interchangeably with "mafia" or "mafioso". It is both a verb and a noun.
It's derived from "gonad", which is a euphemism for "dicks", but you can't call them that lest they'll gonadnarel you. And "narel", from the infamous hooker Nad Narel.
Something 1 out of maybe 100 people has, effectively causing them to be hugely obese. Most obese people who say they have one do not and are making excuses for themselves.
"Nobody will date me because I'm fat!!!", Jeanie wailed as she shoved yet another Ho-Ho in her mouth.