Cheap wine that comes in a box and leaves the consumer with an extreme headache the next day. Convenient because the remains of the vessel can be inflated for use as a pillow after consumption.

when you're hungover as shit after a spending a night drunk as a skunk

an aussie slang term for the those cheap 4 liter wine containers. Due to the excessive drinking in the aboriginal territories and the silver plastic bag inside the carton
the term goonbag evolved.

Extremely cheap wine, the casked form of goon, calling someone a goon bag implies they like goon.

"The Goon Bag" is a specific location in Garema Place, Civic, Canbera City, Australia. This is a common hang out for alternitive sub-cultures, such as goth, emo, indie, punks, etc.

The Goon Bag is a sculpture of a metal over-sized cushion, which is mounted on black marble 'steps' that rise about a meter off the ground.

The actual sculpture was named 'the goon bag' due to it's metal cushion, that resembles the silver bag that cheep wine (also known as goon) comes in.

Someone who is a douchebag and is a freaking idiot.

Goonbag is not just a noun, it's a lifestyle. A goon bag is a person who has no job, doesn't wear shoes, often covered in sand, doesn't go to class, and of course drinks heaps of goon like its fucking water. A goonbag has no money but still blows it all at the casino usually forcing them to eat chicken and cheeses for all three meals. A goonbag BYO's goon to everything they do and solve all of their problems by drinking