What is the meaning of Shill?

A person paid to endorse a product while pretending to be impartial.

Any person enthusiastically endorsing a product; especially, one who is getting paid for the endorsement.

An accomplice at a confidence trick during an auction or gambling game, such as an accomplice of the seller who bids to drive up the price.

A house player in a casino.

To promote or endorse in return for payment, especially dishonestly; sometimes extended sarcastically even to those not paid but strongly biased in favor.

To put under cover; to sheal.

To shell.

Source: wiktionary.org