In all forms of poker, a bluff is a bet made with the intention of getting your opponent to fold their cards and allow you to win the pot, although your actual hand is weak and couldn’t win at a showdown.
For example, you raise on the BTN with 76s and the flop comes AQ2. While you have absolutely nothing, you might want to bluff in this situation since the board is favorable to your range. If your opponent decides to fold a better hand than 7-high, you just bluffed them out of superior holding.
Of course, this is just the simplest example. In poker, there are many different situations where you can bluff by betting or raising a bet in an attempt to convince the opponent that you have a strong hand while your actual hand has no or very little showdown value.
Closely connected to the term bluffing is the expression semi-bluffing. Unlike a pure bluff, a semi-bluff is a bet or a raise made with a hand that’s weak at the time of betting but has the potential of becoming strong on future streets.
One good example of a semi-bluff is when you raise the opponent’s bet with a flush draw. For example, you have Ah6h on a board of Js9h8h. If you raise and your opponent calls, they likely have a better hand on the flop, but you can catch a heart on the turn to give you the nuts.