quietgoer 

Someone who often quite abruptly stops communicating with you. Quietgoers are most often found at the start of the courting process, when selling items online and when looking for jobs but they crop up in all walks of life.

The quietgoer is so called because he/she "goes quiet" on you and will pretty much pretend to be dead to you because they have decided they want nothing more to do with you but don't want to inform you of this fact.

Someone was supposed to collect this oriental rug I have here but he's a quietgoer, havn't heard from him in two weeks and all attempts to contact him failed.

quietgoer by Pineapple Dan August 27, 2015

Quietforce

When you’re a little constipated in a public restroom, you use the quietforce.

I thought I was alone in the airport bathroom until I heard the aggressive splish-splash next to me, he must have used the quietforce.

Quietforce by ShadyMccoyy March 31, 2020

quietlier 

The act of getting more and more quiet until you are something quieter than quiet.

Teacher: "Can you be quietlier?"
Student: "Can you not infringe on my rights?

quietlier by Caesar's Legate October 22, 2020