Definitions by Chris Callan

onzo 

When something is on or when something is so on. When something is going to happen or happen intensely it becomes option to add the zo. It's commonly used when a guy thinks he going to score with a girl. Also used when a guy is about to fight another guy.

Dude it's friggin on tonight.
Dude it's friggin onzo tonight.

onzo by Chris Callan January 12, 2009