The term “Slush Fund” in its modern connotation leaves a dirty taste in most peoples mouths. Common in business and politics, slush funds can have legitimate purposes but are most commonly associated with fallen governments and embarrassed politicians such as Abbott’s secret fund to fight One Nation, the notorious Union political slush funds or even more notorious examples like Nixon’s side hobbies.
The word slush originates as a little bit of onomatopoeia dating back to the mid 17th Century, probably from Swedish “slask” for a damp soggy ground or from the Danish “slus” for sleet. As a side note, on the tree of languages English is damn close to the Germanic and Scandinavian languages (closest relative language being Dutch), hence these are usually the best starting point for any word that does not appear to have Greek or Latin origins.
Slush first appears in English in the 18th century as a reference to the slushy part of animals; the fat. It was almost solely in nautical usage relating to the grease at the bottom of salted meat barrels. The term probably jumped over into English following the naval detente that arose after each of the Anglo-Dutch wars (a somewhat forgotten series of wars during which the English were defeated and sole domain of the Spice Islands was handed to the Dutch.)
It was common practice for the grease at the bottom of these barrels, or the thick layer that rose to the top when boiling, to be saved and sold onshore to candle and soap makers. These sales were treated on a “don’t ask don’t tell” basis by the brass and the proceeds were split between the Officers.
Hence Slush Funds were an off-the-books account used to benefit secret or priority groups, and almost always associated with luxurious purchases. It’s a pretty easy jump to politics. The term first appeared in a political context following the US Civil War. It referred to contingency funds set aside by Congress, outside of the regular budget for special projects and was usually associated with carpet-baggers.
Anecdotally there is usually considered a difference in the legitimacy between Pork-Barrel politics and Slush Funds even though both terms are almost certainly from the same source.
The term “greasing the palm” and its variants are probably also drawn from a reference to slush funds…good to know.