Decelerated 

Comes from the word Deceleration meaning slowing down.
(Decelerated) is used as an insult less specific to certain group of people and focused on the act or behavior of someone instead of the word "Retarded" since retarded meaning is seen as an adjective for disability which is insensitive.

You are decelerated!
What was that decelerated behavior for?
What you just did was decelerated.

Decelerated by DENGOO March 31, 2022

deceleration trauma 

A term describing damage caused by slamming or smashing something.

"My cell phone dropped out of the window and died of deceleration trauma"

deceleration trauma by DanoNYC January 17, 2010

user-degenerated content 

Similar to user-generated content, but failed. The most widely spread type of media on the internet.

Youtube videos showing Dragonball scenes while Nirvana music is playing in the background are user-degenerated content.

user-degenerated content by earl1999 September 19, 2009

decleated 

when you get tackeled in sport real hard. You get knocked out your cleats (shoes).

Boy, that guy just got it De-cleated! He went nowhere fast.

decleated by Lamonator December 20, 2004

Deccelerate 

Accelerate was the lead single from Floptina's comeback album, liberation, that failed to, well, accelerate to the top 10.

Deccelerate down the charts

Deccelerate by hyrule_galaxy June 3, 2019

Deceleration 

The process of taking all the disgusting celery out of your soup.

Eww, dude wtf?! Don't eat your soup without deceleration FFS!

Deceleration by Retto Elbaroda February 18, 2021

Deceleration 

The process of coming down from speed

Aw shit, man. I'm starting to get some deceleration.

Deceleration by Brovahkiin93 June 2, 2016