Meaning

noun a high steep bank (usually formed by river erosion)

noun pretense that your position is stronger than it really is

noun the act of bluffing in poker; deception by a false show of confidence in the strength of your cards

originProbably from Dutch bluffen (“to brag”), from Middle Dutch bluffen (“to make something swell; to bluff”); or from the Dutch noun bluf (“bragging”). Related to German verblüffen (“to stump, perplex”).

Etymology from Wiktionary, CC BY-SA 3.0