rubbish vs slag off

rubbish

verb
  • To criticize, to denigrate, to denounce, to disparage. 

  • To litter. 

noun
  • Nonsense. 

  • Refuse, waste, garbage, junk, trash. 

  • An item, or items, of low quality. 

adj
  • Exceedingly bad; awful. 

intj
  • Used to express that what was recently said is nonsense or untrue; balderdash!, nonsense! 

  • Used to express that something is exceedingly bad, awful, or terrible. 

slag off

verb
  • To talk insultingly to or about someone or something; usually one who is not present. 

  • To purify by melting and removing slag. 

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