Slippage

Slippage is the difference between a trade's expected price and the price actually executed, caused by price movement or token taxes.

On an automated market maker, each trade shifts the pool's reserve ratio, so large orders in thin liquidity execute at a worse price, and that gap is slippage. Traders set a slippage tolerance to allow for it, but honeypots and high-tax tokens exploit this: a sale may need an enormous tolerance to go through or fail entirely, which is itself a warning sign.