A word used by conspiracy theorists when they are losing an argument. The word originally referred to an accomplice of a travelling salesman selling quack remedies or similar items of dubious value. The conspiracy theorist calls their opponent a "shill" in an attempt to discredit them by implying that they are paid agents working for the government, the Bilderbergers, reptilian overlords, the Rotshschilds etc, because of course only such people could possibly disagree with them.

See those trails behind that plane? They're not disappearing within seconds, therefore they must be chemtrails. The government are trying to poison us all, wake up sheeple!!- Ummm, no, persistent contrails are the result of certain atmospheric conditions at certain altitudes, very similar to cirrus clouds. And if the government was trying to poison the population in this way, it would be a very inefficient one and also a very indiscriminate one which would kill the elite as well as the general population. Plus global population has grown from 3.6 million in the 1970s to over 7 billion now - so if they're trying to reduce the world population, they're going about it in a strange way!^^ Shill !!! Disinformation agent!!!