Any and all douchebaggery associated with the use of a guitar, including, but not limited to, (a) whipping one out at a party, (b) playing an overwrought, attention-seeking guitar solo for no reason other than you feel like dominating the stage and are a hopeless fucking douchebag (see: hair metal), owning a flying V - especially for reasons of irony. Especially then.
"Yeah, I made it out to see that Metallica cover band. 5 minute impromptuguitar solo at the end of One. Buncha fuckin' guitarbage, you ask me."
"What is he doing, playing 'Major Tom' in the living room? Total guitarbage. Its funny, I guess, but what a douchebag."
1. The act of shooting squinty-eyed dirty looks at the guitar player in your band (which he, unfortunately never see's because of guitar face!) when he decides to solo LOUDY through the entire song in his usual autistic way.
A guitar owned by someone that cannot play. Often these are obtained in by people who intend to learn, but never muster the motivation to begin/persist.
Steve: Do you know anyone selling an old guitar? I would really like to learn.
John: Ask Peter, he's got a guitornament by the fish tank.