Off your barnett is when you have consumed a large amount of alcohol and/or drugs and are going on a west one.
Example 1:
Henry: "Hey dude, did you see Chris? He has a line of coke and half an E"
Jimmy: "Haha, yeah he's off his barnett"
Example 2:
Tom: "I'm gonna down this whole bottle of vodka"
Jay: "LAD YOU'RE GONNA BE OFF YOUR BARNETT!"
Henry: "Hey dude, did you see Chris? He has a line of coke and half an E"
Jimmy: "Haha, yeah he's off his barnett"
Example 2:
Tom: "I'm gonna down this whole bottle of vodka"
Jay: "LAD YOU'RE GONNA BE OFF YOUR BARNETT!"
by FlappedJoint March 2, 2012