chum vs cobber

chum

noun
  • The chum salmon 

  • A coarse mould for holding the clay while being worked on a whirler, lathe or manually. 

  • A mixture of (frequently rancid) fish parts and blood, dumped into the water as groundbait to attract predator fish, such as sharks 

verb
  • To cast chum into the water to attract fish. 

  • To accompany. 

  • To share rooms with someone; to live together. 

  • To lodge (somebody) with another person or people. 

  • To make friends; to socialize. 

cobber

noun
  • A sweet consisting of a small block of hard caramel covered in chocolate. 

  • A pal, buddy, mate, friend; often used in direct address by one male to another. 

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