A counterfeit representaion of a coin that has similar shape (and possibly similair weight) used to subvert vending machines.
Source: Term at one point was used on the New Jersey boardwalk in the 1980s.
An entity (especially a person) not capable of meeting minimal standard of the productivity that they are participating in, usually used disparagingly.
Source: I use this today as it seems approprite to descibe someone people that can get in your world, but can't deliver.
Posted sign: Those caught using slugs will be barred from this arcade.
Coach Willaims: You call that Rugby?!! I can get 15 slugs off the street to beat you guys