A Shill(er), often referred to as Shilling, describes a person who aggressively promotes an existing cryptocurrency or a new cryptocurrency project for personal benefit. As a result, interest in the advertised cryptocurrency grows, other investors buy it, and the value of the coin or token rises. This gives Shiller the opportunity to sell his own holdings for a higher price and make a profit.
In 2021, the term cryptocurrency Shilling became quite popular as many small cryptocurrency projects paid influencers to increase awareness of their particular project on social media.
See also: Shitcoin, Airdrop, Bounty.