bluff

Etymology 1

Probably 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”).

noun

1. An act of bluffing; a false expression of the strength of one's position in order to intimidate; braggadocio.
   That is only bluff, or a bluff.
2. (poker) An attempt to represent oneself as holding a stronger hand than one actually does.
   John's bet was a bluff: he bet without even so much as a pair.
3. (US, dated) The card game poker.
   BLUFF OR POKER [title of a chapter] 1845, Hoyle's Games
4. One who bluffs; a bluffer.
5. (slang, dated) An excuse.

verb

1. (poker) To make a bluff; to give the impression that one's hand is stronger than it is.
   John bluffed by betting without even a pair.
2. (by analogy) To frighten or deter with a false show of strength or confidence; to give a false impression of strength or temerity in order to intimidate and gain some advantage.
   The government claims it will call an election if this bill does not pass. Is it truly ready to do so, or is it bluffing?
3. To take advantage by bluffing.
   We bluffed our way past the guards.
4. (Manglish, Singlish) To give false information intentionally; to lie; to deceive

Etymology 2

Related to Middle Low German blaff (“smooth”).

noun

1. A high, steep bank, for example by a river or the sea, or beside a ravine or plain; a cliff with a broad face.
   Situated on bluffs above the Huangpu, a tributary of the Yangtze, Shanghai—which means ‘above the sea’—is sinking. 2020, David Farrier, “Thin Cities”, in Footprints, 4th Estate
2. (Canadian Prairies) A small wood or stand of trees, typically poplar or willow.

adj

1. Having a broad, flattened front.
   the bluff bows of a ship
2. Rising steeply with a flat or rounded front.
   a bluff or bold shore 1769, William Falconer, "Côte en écore" (entry in An Universal Dictionary of the Marine)
   Its banks, if not really steep, had a bluff and precipitous aspect. 1845, Sylvester Judd, Margaret: A Tale of the Real and the Ideal, Blight and Bloom; Including Sketches of a Place Not Before Described, Called Mons Christi
3. Surly; churlish; gruff; rough.
4. Roughly frank and hearty in one's manners.
   a bluff answer
   a bluff manner of talking
   a bluff sea captain

Etymology 3

Possibly onomatopoeic, perhaps related to blow and puff.

verb

1. To fluff, puff or swell up.
   Not a sparrow on the cottage thatch, where the chimney's warmth had thawed the snow, that did not seem to have his great coat on, so bluffed out were the feathers, and not a frozen-out duck who did not glance up at the icicles hanging to the roof, and quack a prayer for rain. 1866, Grantley F[itzhardinge] Berkeley, “Incidents of Sport”, in My Life and Recollections. … Complete in Four Volumes, volume III, London: Hurst and Blackett, publishers, successors to Henry Colburn,[…], →OCLC, page 124
   [W]hen the bare boughs of a tree intervened between her and the rising bright but deep red sun, frosted as the twigs were, on them sat a merry flock of sparrows, the feathers on their breasts bluffed out, as if they had donned warm winter spencers to shield them from the biting blast. 1870, Grantley F[itzhardinge] Berkeley, “The Fair Doe of Fernditch”, in Tales of Life and Death. … In Two Volumes, volume I, London: Chapman and Hall,[…], →OCLC, page 117
   I remember one idle bright afternoon here when Phillip bluffed out his little chest, sneaking expectant glances back at me and Cammy, until she "restrained" him from bickering with that beagle. 2002, Nick Fowler, “Sunday in the Park with Sores”, in A Thing (or Two) about Curtis and Camilla, New York, N.Y.: Pantheon Books; 1st Vintage Contemporaries edition, New York, N.Y.: Vintage Books, June 2003, pages 285–286