1. To be completely feed up with something and not give a shit anymore.
2. Used to let someone know they are either drunk and shouldn't drink anymore, (2a)or they've dont something wrong and are gonna get the shit kicked out of them.
1. I hate art school, I'm donezo.
2. Dude, Josh is fighting a dog, he needs to go home he's donezo.
2a. Did you just take my beer?!?! That's it, you're face is DONEZO!!!