Bluff, a.
Etymology: [Cf. OD. blaf flat, broad, blaffaert one with a broad face, also, a boaster; or G. verblüffen to confuse, LG. bluffen to frighten; to unknown origin.]
1. Having a broad, flattened front; as, the bluff bows of a ship. "Bluff visages." Irving.
2. Rising steeply with a flat or rounded front. "A bluff or bold shore." Falconer. Its banks, if not really steep, had a bluff and precipitous aspect. Judd.
3. Surly; churlish; gruff; rough.
4. Abrupt; roughly frank; unceremonious; blunt; brusque; as, a bluff answer; a bluff manner of talking; a bluff sea captain. "Bluff King Hal." Sir W. Scott. There is indeed a bluff pertinacity which is a proper defense in a moment of surprise. I. Taylor.
3 other Webster entries under this spelling
Bluff, n.
1. A high, steep bank, as by a river or the sea, or beside a ravine or plain; a cliff with a broad face. Beach, bluff, and wave, adieu. Whittier.
2. An act of bluffing; an expression of self-confidence for the purpose of intimidation; braggadocio; as, that is only bluff, or a bluff.
3. A game at cards; poker. [U.S.] Bartlett.
Bluff, v. t. [imp. & p. p. Bluffed; p. pr. & vb. n. Bluffing.]
1. (Poker)
To deter (an opponent) from taking the risk of betting on his hand of cards, as the bluffer does by betting heavily on his own hand although it may be of less value. [U. S.]
2. To frighten or deter from accomplishing a purpose by making a show of confidence in one's strength or resources; as, he bluffed me off. [Colloq.]
Bluff, v. i.
To act as in the game of bluff.
Shades of meaning
Bluff is a word of good meaning, as are frank and open. The bluff man talks and laughs loudly and freely, says and does whatever he pleases with fearless good nature, and with no thought of annoying or giving pain to others. The blunt man says things which he is perfectly aware are disagreeable, either from a defiant indifference to others' feelings, or from the pleasure of tormenting.