In the card game of
poker, to
bluff is to make a bet despite holding a hand which one does not expect to be the best hand. The objective of a bluff is to induce a
fold by at least one opponent who holds a better hand. The size and frequency of a bluff determines its profitability to the
bluffer. By extension, the phrase "calling somebody's bluff" is often used outside the context of poker to describe cases where one person "demand[s] that someone prove a claim" or prove that he or she "is not being deceptive."