Bluff
Betting or raising with a weak hand to make opponents fold better hands and win the pot without a showdown.
Definition
A bluff is a bet or raise made with a hand that is probably not the best, intended to make opponents fold hands that would otherwise win. Bluffing is possible because of poker's hidden cards: opponents cannot see that you are weak. A 'pure bluff' has little chance of winning at showdown, while a 'semi-bluff' bets a drawing hand that can also improve to the best hand later, combining fold equity with real equity. Effective bluffing depends on telling a believable story, choosing opponents who can fold, and balancing bluffs with value bets so you are not predictable. Bluffing too often against players who never fold is a common and costly mistake; bluffing is a tool, not a default.
Worked example
On a scary board showing three cards to a flush, a player with no flush fires a large river bet, representing the flush; the opponent folds a strong-but-beatable hand, and the bluff wins.
Why it matters
Learners need to see bluffing as a calculated, situational tool rather than the essence of poker, and to avoid bluffing players who will not fold. Professionals bluff at balanced frequencies tied to their value bets, making them hard to read and their value bets more profitable.