butty vs oppo

butty

noun
  • Friend. 

  • A miner who works under contract, receiving a fixed amount per ton of coal or ore. 

  • A sandwich, usually with a hot savoury filling in a breadcake. The most common are chips, bacon, sausage and egg. 

  • A workmate. 

oppo

noun
  • A friend, associate or colleague. 

  • Research into one's opponent's family, friends, and past, which aims to uncover activities or interests which embarrass or discredit them. 

How often have the words butty and oppo occurred in a corpus of books? (source: Google Ngram Viewer )