walloper

plural wallopers

1. One who wallops.
2. IrelandA cudgel, a shillelagh.
3. ScotlandderogatoryslangvulgarThe penis.
4. ScotlandbroadlyderogatoryslangvulgarAn idiot; a stupid person.
5. AustraliaA police officer.

   Police! Everyone out! The bloody wallopers are on their way!

   1950, Frank Hardy, Power Without Glory

   2 more examples

   Two days later we were picked up by the wallopers on Clucas' information.

   2001, Richard Flanagan, Gould's Book of Fish, Vintage, published 2016, page 84

   Understandably the wallopers were called, and they cleared everybody out.

   2006, Andrew Stafford, Pig City: From the Saints to Savage Garden, page 106

   Synonyms: police officer

6. slangSomething big; a whopper.

   I'd had some wonderful fishing, but I hadn't landed a real walloper.

   1969, Field & Stream, volume 74, number 1, page 138