A poker player will use the term pot committed when trying to convey that they’ve already put so much money into the pot that they now have to call the opponent’s bet even if they believe their chances of winning are slim.
For example, say the board is 5s7sKdJs, and you have a small flush with 3s4s. Your opponent bets, you raise them, and they call. The river comes to Ts, bringing four to the flush. Your opponent moves all in, but he only has $20 behind, and there is already $400 in the pot.
Although you’re now losing to any higher spade, you are getting so good pot odds that you’re pot committed, and you have to call, just in case your hand is still good. To avoid getting into such situations, players can use various strategies to pot control.
