Sometimes abbreviated as "Dr. Killjoy." Coined by N.E.R.D in the song "Anti Matter." A Doctor Killjoy is someone who makes it their business to ruin, take large dumps on, and/or "shoot up" your party or the party you are attending.
Person 1: Haha, I just pooped on your carpet, man!
Person 2: Why you doctor Killjoy, shooting up the party?
Person 2: Why you doctor Killjoy, shooting up the party?
by Achilles015 June 6, 2009

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.
by EvilMuse April 12, 2005

by †wiligh† November 21, 2007

Professor Killjoy fucked your mom and most likeley hates you! He also likes to hit bunnies with his car
by Muas March 15, 2003

by Maus March 15, 2003

the punchline to an.. inappropriate, mini comic made by a frerardshipper (shipper of Gerard way and Frank Iero of my chemical romance).
standard fiatfv fan: hey look! It’s the stream for the medicine square garden music video
frerard shippers in the live chat: ARMS BACK KILLJOY
frerard shippers in the live chat: ARMS BACK KILLJOY
by semop May 19, 2020

by Crashkiller January 5, 2020
