A honeypot token is a trap disguised as an exciting new coin. You can buy it easily, but when you try to sell, the transaction fails every time.
The trick lives inside the token's smart contract. The code is written so that only the creators can sell, while everyone else is blocked. Meanwhile the price on the chart often looks like it is soaring, because buyers keep pouring in and no one can cash out. That rising number lures in more victims. Eventually the creators sell their own holdings, collect all the trapped money, and the token collapses to nothing.
The name comes from the idea of a pot of honey that attracts and then traps.
Spotting one is hard for a beginner, which is the real lesson: be extremely cautious with brand-new tokens promising huge, fast gains. If a coin's price only ever goes up and you cannot find anyone who has successfully sold it, treat that as a serious red flag.