Denader 

Someone who will seem fun at first glance, then you realize that he gets boring really fast, and eventually starts to stalk you or one of your friends.

He is a denader man" "that guy has turned into such a denader" "how often has he been dednading you?

Denader by Denading Denader May 28, 2011

Deader than a doornail

When something is so dead as to not have any life left in it , as not to even be able to be revived .

I don't think I'm gonna be able to get your car started , that battery is deader than a doornail !

Deader than a doornail by dragonboy8586 June 22, 2020

deader 

To make something deader, you must first kill it, then kill it a second time (and maybe a third time, just to be on the safe side)

I killed Shmouze, and to make sure he didn't come back as a zombie, I made him deader.

deader by CartlidgeIsGay December 30, 2008

deadernshit 

Something so dead it could literally be a pile of dung extract.

*Horse falls over dead* The owner walks up to it and says, “welp, my horse is deadernshit.”

deadernshit by Boots7 November 4, 2020

deader than Kristen Stewart's eyes 

adjective
Something so lifeless or useless (dead) that it out-deads even the lifeless-ness of Kristen Stewart's acting. This term first coined by Maria Walters, aka Masala Skeptic of Skepchick in the post "Reclipse: Yes, Twilight still sucks"

Zombies' brains are deader than Kristen Stewart's eyes.

deader than Kristen Stewart's eyes by ariklkira November 14, 2012

denderfiliac 

Having sex with a tree

Tree:I'm a tree
Nick:I know

denderfiliac by Ashley July 31, 2004

denderphiliac

To have sex with trees

... you fuck trees nuff said

denderphiliac by Me February 20, 2005