Alcohol-induced bravery or braggadocio. "Geneva" is a type of gin made in the Netherlands and is sometimes capitlized. There goes Rich, picking a fight with someone at the bar. Looks like the geneva courage has kicked in! He thinks he's the smartest guy in the room when he's feeling some Geneva courage.
See also: courage
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.