Literally, in Yiddish it means "beans". However, beans was a term used to describe goat droppings, as goat shit looks like beans.
So bupkis or bupkes is a common slang for, 'of no value". That is what the slang means. The reason for that is above. It does not literally mean "goat shit". It means "beans".
A woman's saggy butt that developes after having kids and loosing some weight. Resembling a pumpkin that has melted and sagged after sitting on the porch too long after Halloween.
Man, Aubri used to be hot in high school, but now that she has had kids she has bumpkin butt.
Also spelled bubkes but still means the same thing. The word Bupkis means 'nothing, zero, having no value'. Also it is said by the television character Dr. Zoidberg on the show "Futurama" since he is a Jewish lobster and this word has a Jewish origin it all makes sense.