blacken vs rasher

blacken

verb
  • To make dirty. 

  • To defame or sully. 

  • To cook (meat or fish) by coating with pepper, etc., and quickly searing in a hot pan. 

  • To become black. 

  • To cause to be or become black. 

rasher

verb
  • To cut into rashers. 

noun
  • A strip, a piece (of something, such as ham, bacon, etc). 

  • A strip of bacon; a piece of bacon. 

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