1. Police code for a person that is a danger to him/herself.

2. Often used by gangster and thugs as a person that is psycho enough to put his/her or anyone else's life on the line.

3. Can be a reference to a trance like episode were the person doesn't care about the law, life or anything around.
1. "I'm going to need assistance with a 51 50 on 12th st." - officer Doofy

2. Miss 5150 is a hot piece but I heard that she is straight up psycho and she is down for that BLU flag.

3. That slob better quit clowning or I'm going to have to go 51 50 on his ass.
by The EVIL BATMAN March 29, 2010
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California police code for a "crazy". Also the name of Eddie Van Halen's home recording studio... and a name of a Van Halen CD.
No example is needed.
by VHFan November 14, 2003
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When your labeled by police or doctors as being an endangerment to yourself and others. Once labeled as 51/50, you get taken to a pysch ward for a 72 hour hold to see if your mentally stable.
He threatened to beat up his parents, so they called the cops & they 51/50'd him.
by jdmvero April 5, 2010
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police code meaning crazy and violent. often used as slang meaning the same.
cop: "we have a 51/50 here. im gonna need backup."

person: "that dude's a fucking 51/50. dont mess with him."
by Kennedi Greene August 22, 2007
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A group of mentally retarded children who think they are special for sitting in a GM's pocket.
What an idiot...must be part of the 51-50.
by Anyone Respectable July 15, 2004
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when yo ass goes fuccin crazy an kills sombody
we got a 51-50 down on 1st street
by Fatal November 12, 2003
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Someone who the police, with their poor grasp of psychology, think is a danger to themselves or others. They will generally yell at someone and if they yell back enough, declare them a 51/50. FUCK THE POLICE.
I was in the hospital and some big angry police guy yelled at me and I yelled back, so they gave me the 51/50.
by Downvoting Victim August 21, 2009
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