Something uncommonly large of the kind; something astonishing; -- applied especially to a bold lie. Now (1998) usually spelled whopper. [1913 Webster]

whopper, n. [Cf. Whapper.].

One who, or that which, whops. [1913 Webster]
something very large, especially a big lie. Same as Whapper, but the more common spelling. [1913 Webster]

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OXFORD DICTIONARY

whopper, n. sl.
1 something big of its kind.
2 a great lie.

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ROGET THESAURUS

whopper

Untruth

N untruth, falsehood, lie, story, thing that is not, fib, bounce, crammer, taradiddle, whopper, jhuth, forgery, fabrication, invention, misstatement, misrepresentation, perversion, falsification, gloss, suggestio falsi, exaggeration, invention, fabrication, fiction, fable, nursery tale, romance, absurd story, untrue story, false story, trumped up story, trumped up statement, thing devised by the enemy, canard, shave, sell, hum, traveler's tale, Canterbury tale, cock and bull story, fairy tale, fake, claptrap, press agent's yarn, puff, puffery (exaggeration), myth, moonshine, bosh, all my eye and Betty Martin, mare's nest, farce, irony, half truth, white lie, pious fraud, mental reservation, pretense, pretext, false plea, subterfuge, evasion, shift, shuffle, make-believe, sham, profession, empty words, Judas kiss, disguise, untrue, false, phony, trumped up, void of foundation, without- foundation, fictive, far from the truth, false as dicer's oaths, unfounded, ben trovato, invented, fabulous, fabricated, forged, fictitious, factitious, supposititious, surreptitious, elusory, illusory, ironical, soi-disant, se non e vero e ben trovato, where none is meant that meets the ear.

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