Retard 

The only word in the world that is considered offensive when used properly and used improperly. If used as a replacement for the word stupid someone will immediately point out how you're being offensive. On the contrary, if you call someone who is mentally handicapped retarded, you will also be called offensive.

Person one: You just chugged a 2 liter of Coke and a box of Mentos? You retard.
Person two: Hey, that's offensive! (Proceeds to vomit Coke everywhere)

Person one: Aww, poor Timmy is retarded.
Person two: Hey, that's offensive!

Retard by Mr. P. FLuffee June 16, 2010

retard 

to tard again

Joe tard-ed once, and then once again.

Retard.

retard by A1steak October 6, 2011

retard 

1. A person with a mental deficiency
2. An offensive term used to refer to someone acting in an irritating or generally stupid way.

retard by Tom September 17, 2003

Retard 

It means someone is stupid.

Jimmy: 2+2=51
Tom: Jimmy You are a retard

Retard by FrizzlePlayz April 27, 2017

retard 

People who think they have to take their pets with them everywhere they go.

That retard left their dog in the hot car with the windows rolled up at Walmart again.

retard by Spanky420247 May 1, 2014

Retard 

Aidan

Aidan is retarded

Retard by Amped273 November 19, 2018

retard 

The second most abused word in the English language, next to gay.

Bob: I got a 72% on my math test.

John: RETARD! I got a 75%.

retard by Little Johnny's Big Brother March 9, 2010