What is a Blocker?

Blockers are cards that make it less likely for an opponent to make a hand.  For instance, if you are holding pocket 8s and the board flops 9, 7, 6, other players are less likely to have a straight, since you hold blockers; two of the four cards they need to complete the hand.  A blocking bet is typically small (in relation to the pot size) and is usually made out of position on the river to get to a cheap showdown.

By Howard Hian