whacker

plural whackers

1. One who, or something which, whacks.

   Joe was just about the best Australian heavyweight at the time, a very tough customer in his own right. He didn't have any science, but he was a mighty whacker.

   1963, George Blaikie, Scandals of Australia's Strange Past, Adelaide: Rigby Limited, page 117

2. informalSynonym of whopper (“anything large”).

   Synonyms: whopper

3. informalSynonym of whopper (“an outrageous or blatant lie”).

   "Oh, there's a whacker!" cried East; "we haven't been within a hundred yards of his barn; we haven't been up here above ten minutes, and we've seen nothing but a tough old guinea-hen, who ran like a greyhound."

   1857, Thomas Hughes, Tom Brown's School Days

   1 more example

   But all the while Captain Amos Brown was telling whackers that would have done credit to Baron Munchausen, he was really thinking of how he was to save those whose passage to a port not named in any bills of lading looked almost certain.

   1908, Morley Roberts, “The Captain of the Ullswater”, in The Blue Peter

   Synonyms: whopper

4. slangA radio amateur who is keenly interested in emergency response and may travel to the sites of emergencies.