1) American sandwich 2) Big lie 3) Prevarication 4) Prodigious prevarication 5) Walloper 1) Fib 2) Giant 3) Lie 4) Lulu 5) Tale 6) Tall story 7) Tall tale 8) Untruth 9) Whacker 
The Whopper sandwich is the signature hamburger product sold by the international fast-food restaurant chain Burger King and its Australian franchise Hungry Jack`s. Introduced in 1957, it has undergone several reformulations including resizing and bread changes. The burger is one of the best known products in the fast food industry; it is so well....
• (n.) Same as Whapper. • (n.) Something uncommonly large of the kind; something astonishing; -- applied especially to a bold lie. • (n.) One who, or that which, whops.
Whop'per noun [ Confer Whapper .] 1. One who, or that which, whops. 2. Same as Whapper . 
Whopper is slang for something very large.
[n] - a gross untruth
walloper noun a gross untruth; a blatant lie
Massive, and therefore great. Not to be confused with the burger.