Impermanent loss happens when you provide liquidity to a liquidity pool, and the price of your deposited assets changes compared to when you deposited them. The bigger this change is, the more you are exposed to impermanent loss. In this case, the loss means less dollar value at the time of withdrawal than at the time of deposit.
So why do liquidity providers still provide liquidity if they’re exposed to potential losses? Well, impermanent loss can still be counteracted by trading fees. In fact, even pools on Uniswap that are quite exposed to impermanent loss can be profitable thanks to the trading fees.
Uniswap charges 0.3% on every trade that directly goes to liquidity providers. If there’s a lot of trading volume happening in a given pool, it can be profitable to provide liquidity even if the pool is heavily exposed to impermanent loss. This, however, depends on the protocol, the specific pool, the deposited assets, and even wider market conditions.