Killjoy 

Medal for the popular video game Halo 3. The Killjoy medal's purpose is to indicate when a player ends an opponent's spree, any spree of any kind. The symbol for the killjoy is a smilet with the "NO" symbol going through it.
When the medal is achieved, the announcer says "Killjoy"

"KILLJOY!"

Chris000 ended douchykinz's killing spree

Killjoy by Chris000 January 17, 2008

Killjoy 

Someone who is boring and thinks everything is weird and acts like the teenagers from "Hannah Montana".

Why do killjoys have to be so closed-minded? They need to get a grip!

Killjoy by iLikeWatermeons33 November 28, 2012

killjoy 

Someone who infringes on your trips, man.

Me: *Smoking a bong*
Mom: No way, my child.
Me: Shut up biotch, don't be a killjoy.

killjoy by rabidwalrus November 4, 2009

Killjoy 

Someone (usually Michael S.) who enjoys needlessly pointing out logical flaws by responding to internet conversations (that they weren't originally included in) with copious amounts of obscure (or useless/stalkerlike) information

Adam: "yeah, according to this list, the **** champs are ranked 22nd...that can't be right"

Mike: (ignoring **** reference) BLAHBLAHBLAHBLAH I SURF FORUMS ALOT AND LEARN ABOUT OTHER TEAMS THAT I'VE NEVER TALKED TO NOR COMPETED AGAINST BLAHBLAHBLABLAH THIS IS WHY YOU'RE WRONG BLAHBLAHBALHABLAH

A: You're a killjoy.

Killjoy by Pissedofffacebookguy March 14, 2011

killjoy 

KillJoy Radio where the web will kick your ass!!. Can be found easily by going to the shoutcast site and searching for KillJoy. Also found onirc on undernet #killjoy.

Killjoy Radio, don't let the name fool ya!

killjoy by EvilMuse April 12, 2005

Killjoy 

An idiot or someone so stupid they can't open a door.

Killjoy, you're suck a fucking retard... use google if you can't find the game.

Killjoy by †wiligh† November 21, 2007

killjoy 

asshole/s who ruin your best friends funny joke

Guy 1: And he was like laughing so hard
Guy 2: *chuckles*
Guy 3: your joke is so ugly as hell
Guy 1 and 2: what a pathetic piece of killjoy garbage

killjoy by GoodGuyJayce May 11, 2019