GABOS Share definition Flag Prison lingo. Acronym for 'Game Ain't Based on Sympathy,' first heard in the Louis Theroux documentary 'Miami Mega Jail.' Louis: Don't... don't you feel sympathy for that person? For that other inmate you extorted? Inmate: GABOS, man... GABOS. GABOS by KRA_ October 23, 2011 Get the GABOS mug.