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8.
someone who kills joy.
isn't that obvious.
by calV April 30, 2005
 
9.
People who are douche bags and have to ruin the fun of everything, kill the mood or shoot everything down.
Jamie: "Naw, I think I'm going to skip out on the concert, chillin' with friends and going camping."
Caitlin: "Jamie you're such a fuckin' kill joy!"
by Caitlin July 01, 2005
 
10.
Peepz who kill the fun by wanting to do something else or calling it a day/night too early (like me).
"Ay I gotta go. I gottta see my friend so...just watch the rest of GLADIATOR without me, aightz?"

"You're such a KILL JOY!"
by Joshiro007 February 24, 2003
 
11.
The new super heros of the world, out to bring colour and spread the message of the ugly truth to the rest of this conformist society.
We were created by My chemical romance thanks to their new album "Danger days - the true lives of the fabulous Killoys"
The original Killjoys consist of Pary Poison (Gerard Way) Jet star (Ray toro) Fun ghoul (Frank iero) and Kobra kid (Mikey way).
The names of these killjoys have also been rumoured to have something to do wih President JF kennedy, this is due to PJFK the first leters of he bands killjoy names. there is also a kennedy reference in the popular single from he album "NANANA", and the album its self was released on kennedys 50th aniversary. coincedence?
Many of the fans of my chemical romance (the MCRmy) have now adapted the name Killjoy and have even given theirselves killjoy names of heir own such as "NeonDeath" or "Rainbowninja". Killjoys typically dress in bright coloured biker jackets, tight jeans, biker boots, bright bandanna/ helmet/ mask, and wear shoe-laces tied round their wrists or wear gloves.
Killjoys carry a brighly coloured Ray-Gun for fighing the enemy (Draculoids).
Killjoys often have brightly coloured hair (inspired by gerard way's crimson red hair).
The Killjoys of the MCRmy will fight for what is right for what they believe and for the band that they love.
"Killoys, make some noise!"

person 1 : "whats she wearing?"
person 2: "her killjoy oufit."
person 1: "whats that?"
person 2 :" its an MCR thing".

(See Danger Days- the true lives of the fabulous killjoys)
by Amyneondeathkilljoy June 28, 2011
 
12.
One who does not conform to society or corporations; Rebel
"The future is bulletproof
The aftermath is secondary
It's time to do it now and do it loud
Killjoys
Make some noise"
by Killjoys March July 14, 2014
 
13.
A person who intentionally takes the joy of another person and brutally murders it with no remorse.
Girl: Yesh, finally Full Metal Alchemist. Oh how I've longed for you. *kisses television*
Mom: No FULL METAL ALCHEMIST. Japan is evil.
Girl: Geez Mom, you're such a kill-joy!

Girl: Yesh, No school because of snow!
Weather Man: Looks like school is back in session due to the sudden elevation of tempurature.
Girl: Geez Mr. Meteorologist Man Guy, you're such a kill-joy.
by Buttonsinfallcolours August 09, 2006
 
14.
People who consider themselves fans of My Chemical Romance. It's a relatively new term, emerging after the release of their fourth album, Dander Days: True lives of the fabulous Killjoys. Killjoys are often rebellious, and express their rebellion through music, art, or literature. As such, they're somewhat well-know for being artistically gifted in those and other areas. Sometimes, a killjoy will give him/herself a "killjoy name," which is usually an exciting, unique adjective followed by an equally exotic noun.
Killjoys, make some noise!
by Sykoh July 07, 2011