The term “runner” in poker is usually used to describe the cards needed by the player to improve their hand on the final community cards (the turn and the river) and hit the winning combination.

A runner-runner means that the player needs two consecutive cards (one after the other) on the turn and the river to improve their hand. For example, if the player has two cards of the same suit (e.g., two spades), and on the flop and on the turn they get cards of a different suit, they need a runner-runner (two consecutive cards of the same suit) on the turn and the river to hit a flush (five cards of the same suit).

Using the term “runner-runner” usually indicates that the player needs a fairly lucky coincidence on the last two cards to improve their hand and be in with a chance of winning. This is often a long shot and is not always a successful strategy, but in rare cases, it can lead to big winnings.