A strange phenomenon that occurs when a man sees an opportunity to lecture a woman in his life about why it's wrong to enjoy something she enjoys, whether it be silly laughter he doesn't understand among friends or a dessert or admiring her own beauty in the mirror. He has something negative to say because of his own inner turmoil, but he takes it out on the woman. He needs to feel like he's smarter and misery loves company.
This could also be true coming from a woman, or parent to child, child to parent, friend to friend or anyone to anyone. Sadly, I have had a lot of people try to be killjoys in my life, so I never try to be one toward others.
"Everytime I try to get laid, there is a killjoy."
"Calorie Cops are killjoys."
"Killjoys are sadistic."
"Everybody treats killjoys like crap. That's why they are the way they are."
by MadamexXx February 25, 2009

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug
You ended a opponent's killing spree. Medal on Halo 3 after ending a opponent's killing spree.
My opponent killed 5 opponents without dying. I killed him after that to receive the killjoy medal.
by Mr. Chad Allen October 08, 2007

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug
1: Someone who ruins someone else's fun.

2: A fan of the progressive 90's Canadian punk band, The Killjoys.
1: Max took the band out, and Conan the killjoy got peeved, and screamed at them. The party was ruined.

2: "Today I Hate Everyone" is Kev's favorite song, he's a total killjoy
by cheeseplaydoh August 11, 2004

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug
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.
by rabidwalrus October 07, 2009

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug
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.
by Pissedofffacebookguy February 27, 2011

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug
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!
by EvilMuse April 12, 2005

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug
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.
by †wiligh† November 01, 2007

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug