shill

Professionals licensed to shill won't necessarily knock you dead, but they may not do you any good either. They might simply be pitchmen employed to extol the wonders of legitimate products. But in the early 1900s, when the first uses of the verb shill were documented, it was more likely that anyone hired to shill you was trying to con you into parting with some cash. Practitioners were called shills (that noun also dates from the early 1900s), and they did everything from faking big wins at casinos (to promote gambling) to pretending to buy tickets (to encourage people to see certain shows). Shill is thought to be a shortened form of shillaber, but etymologists have found no definitive evidence of where that longer term originated.