Definition of "flabbergast"

Now we are flabbergaſted and bored from morning to night—in the ſenate, at Cox's muſeum, at Ranelagh, and even at church.

1772, “Observator” [pseudonym], “On New Words; from the Same [Town and Country Magazine]”, in Edmund Burke, editor, The Annual Register, or A View of the History, Politics, and Literature, volume XV, London: Printed for J[ames] Dodsley, […], published 1773, page 191, column 1

They flabagast good manners and good morals, and only show that one of the parties is vex'd and disappinted.[sic]The author was known to write in American vernacular for purposes of humor. As a result, the spelling in this work is idiosyncratic.

1834, Jack Downing [pseudonym; Seba Smith], chapter XXV, in The Life of Andrew Jackson, President of the United States, Philadelphia, Pa.: Published by T. K. Greenbank, page 183

Now, there are assertions, not dissimilar in their power of benumbing and flabbergasting one, but yet within the bounds of sane and perfectly orderly plausibility, for which our language wants a name. Paradox is too hackneyed a term. They ought to be called Buckleisms. When a man makes an assertion clean in the teeth of all previous belief, and makes it coolly, fluently, without proof, and yet as if contradiction were impossible—that is a Buckleism.

1861 August, [David Masson], “Mr. Buckle’s Doctrine as to the Scotch and Their History”, in David Masson, editor, Macmillan’s Magazine, volume IV, number 22, Cambridge, London: Macmillan and Co. […], part II (The Weasel-wars of Scotland and the Scottish Reformation), page 316, column 1

Skates that are not quite a fit, my dear Smith, / May flabberghast even a chap of your pith.

1887 January 29, “The ‘Emergency-Man’”, in Punch, or The London Charivari, volume XCII, London: Published at the office, 85, Fleet Street, page 54, column 1

At this I was rendered completely flabaghast—for, although the allegation was undeniably correct, I had confidently hoped that my friend Ram was unaware of the fact, or would at least have the ordinary mother-wit to refrain from blurting it out!

1896 August 22, [F. Anstey] [pseudonym; Thomas Anstey Guthrie], “Jottings and Tittlings. (By Baboo Hurry Bungsho Jabberjee, B.A.) No. XXI. Mr. Jabberjee Halloos before He is Quite Out of the Woods”, in Punch, or The London Charivari, volume CXI, London: Published at the office, 85, Fleet Street, pages 88–89, column 2

Well, some degree of the same pleasure may be experienced when one flabbergasts some romantic Schiller, by putting out one's tongue at him when he least expects it.

1915, Fyodor Dostoevsky, chapter X, in Constance Garnett, transl., The Insulted and Injured: A Novel in Four Parts and an Epilogue [...] From the Russian (The Novels of Fyodor Dostoevsky; VI), London: William Heinemann, part III, page 243

He [Franklin Delano Roosevelt] loved to flabbergast his associates by announcing some startling new policy without consulting any of them.

1956, John T[homas] Flynn, “The Rabbits Go Back in the Hat”, in The Roosevelt Myth, revised edition, New York, N.Y.: Devin-Adair Publishing Company; reprinted Auburn, Ala.: The Ludwig von Mises Institute, 2008, book 1 (Trial—and Error), pages 50–51

The idea may surprise you, but I intend that it shall flabbergast the poor foolish Englishmen mured up behind those pine and redwood logs. Flabbergast 'em, I say!

2008, Harry Turtledove, The United States of Atlantis: A Novel of Alternate History, New York, N.Y.: Roc/New American Library, page 240

Then the most unbelievable thing happened, totally flabbergasting every student in the class.

2012, Tara M. Tamasi, Ms. O’Brien’s Class, [Bloomington, Ind.]: Xlibris, page 226

Her foibles were flattery, fine feeling, and flabergast; and if not old enough to be his mother, sufficiently so to be a young aunt.

1852 October, “Adventures of Tom Honeycomb—No. I”, in Yankee Notions, volume 2, number 10, New York, N.Y.: Published by T. W. Strong, […], page 297

Then quit your flabbergast, and talk in plain English.

1868 February 22, Oliver Optic [pseudonym; William Taylor Adams], “Freaks of Fortune; or, Half Round the World”, in Oliver Optic, editor, Oliver Optic’s Magazine. Our Boys and Girls, volume III, number 60, Boston, Mass.: Published by Lee and Shepard, […], chapter XVI (Pistols for Two), page 117, column 2

Bob's big-eyed flabbergast struck him as comic and he laughed and said, "Lying sack, hey?"

1998, James Carlos Blake, Red Grass River: A Legend, New York, N.Y.: Avon Books; 1st Perennial edition, New York, N.Y.: Harper Perennial, 2000, page 52