Noun. Slang word for money, especially that obtained by criminal, illegal, or generally shady practices, e.g. selling drugs, prostitution, slave trading. Can also mean a pay check while working as an illegal immigrant. Used first by people in the black market and the Mafia.
Additionally, To 'give someone the mudsack' generally means to pay someone for doing something sneaky for you that you didn't want to do yourself.
Jones: "So, Tommy, did you bring me the mudsack?"
Tommy: "Oh man! Jeez, I was too busy running away from the cops to pick it up!"
A person that has agreed to go to an event, but every time they open their mouth there is an excuse as to why they are late and never end up making it.
The saying seems to have started in Santa Barbara during a bachelors party weekend, the longjaw mudsucker is typical from the area.
I just called Marin to see why he was late, but all I heard was excuses as to why he was late. I don't think he's going to make it, he is such a longjaw mudsucker.