bang Share definition Flag 1) Sound made by any pneumatically inflated object when burst. 2) Slang word for sex. 1) "Just a couple more puffs and your baloon will be full" BANG!!!! 2) Stu: So, what did ya do last night? Al: I banged my girlfreind man. bang by Wise Man October 9, 2003 Get the bang mug.