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1.
Crazy, as used in "Wedding Crashers".
I'm terrified of this girl. She's completely off the reservation.
by JtotheL March 01, 2006
 
2.
Going of the reservation is when certain elements such as spies or assassins either fail to complete an assignment/mission, go on an unauthorized mission, get caught and spill their guts, or go rogue. Usually resutlting in the need to neutralize(kill their ass) the said element.
lopez: hey man did you hear about that guy joe who worked with me at the CIA?
jimmy: no man what?
lopez: he went off the reservation and so I had to kill his stupid ass for going rogue.
jimmy: well thats what you get for trying to fucking double cross the CIA.
by mr. shakedown September 04, 2005
 
3.
A term sometimes used when a made man in the mafia kills another made man without the permission of his superiors.

A term sometimes used when agents in a spy agency, such as the CIA, go on unathorised assignments.
The Sopranos: "Tony B went off the reservation and wacked Billy Leotardo."

Spy Game: "If you go off the reservation, I will not come after you..."
by Fablo April 27, 2007
 
4.
a point in time when highly intoxicated or in another state of mind, may result in streaking and/or skinny dipping and blurred memories of the night before.
tonight im going off the reservation, please pick me up in the morning
by YouLikeThis-JMART April 29, 2011